Application Setup

Introduction

.

Practical Learning: Introducing the Application

1. Start Microsoft Visual Studio
2. In the Visual Studio 2022 dialog box, click Create a New Project
3. In the Create a New Project dialog box, in the Languages combo box, select C#
4. In the list of projects templates, click Windows Forms App
5. Click Next
6. Change the Project Name to StellarWaterPoint4
7. In the Framework combo box, select the highest version: .NET 9.0 (Standard Term Suppot)
8. Click Create
9. To create a folder, in the Solution Explorer -> Add -> Folder
10. Type Models as the name of the folder
11. To create a class, in the Solution Explorer, right-click Models -> Add -> Class...
12. On the main menu, click Project -> Add Class...
13. Replace the name with AccountType
14. Click Add
15. Change the code as follows:

    namespace StellarWaterPoint4.Models
    {
        internal readonly record struct AccountType
        {
            public readonly string? TypeCode       { get; init; }
            public readonly string? TypeDecription { get; init; }
        }
    }

16. In the Solution Explorer, right-click Models -> Add -> Class
17. Set the file Name to Repository
18. Click Add

The Main Form of the Application

.

Practical Learning: Preparing the Main Form of the Application

1. In the Solution Explorer, right-click Form1.cs and click Rename
2. Type WaterDistribution (to get WaterDistribution.cs) and press Enter
3. Read the message on the message box and click Yes
4. Click the body of the form to make sure it is selected.
   In the Properties window, change the following characteristics:
   Text: Stellar Water Point
   StartPosition: CenterScreen
   MaximizeBox: False
5. Double-click an unoccupied area of the form to generate its Load event
6. Implement the event as follows:

   namespace StellarWaterPoint4
   {
       public partial class WaterDistribution : Form
       {
           public WaterDistribution()
           {
               InitializeComponent();
           }
   
           private void WaterDistribution_Load(object sender, EventArgs e)
           {
               Directory.CreateDirectory(@"E:\Stellar Water Point2");
   
               Repository.CreateAccountsTypes();
           }
       }
   }

Water Meters

Introduction

.

Practical Learning: Displaying Water Meters

1. To create a class, in the Solution Explorer, right-click Models -> Add -> Class...
2. On the main menu, click Project -> Add Class...
3. Replace the name with WaterMeter
4. Click Add
5. Change the code as follows:

   namespace StellarWaterPoint4.Models
   {
       internal record WaterMeter
       {
           public string? MeterNumber { get; set; }
           public string? Make        { get; set; }
           public string? Model       { get; set; }
           public string? MeterSize   { get; set; }
       }
   }

6. In the Solution Explorer, right-click StellarWaterPoint1 -> Add -> New Folder
7. Type WaterMeters as the name of the folder

Displaying Water Meters

To let the user see a list of the water meters in the database, we will use a form equipped with a list view.

Practical Learning: Displaying Water Meters

1. To create a form, in the Solution Explorer, right-click WaterMeters -> Add -> Form (Windows Forms)...
2. For the Name of the form, type Central
3. Click Add
4. In the Toolbox, click the ListView button and click the form
5. On the form, right-click the list view and click Edit Columns...
6. Create the columns as follows:

   (Name)	Text	Width	TextAlign
   colWaterMeterId	Id	40
   colMeterNumber	Meter #	150	Center
   colMake	Make	300
   colModel	Model	150
   colMeterSize	Meter Size	150

7. Click OK
8. Position and resize the list view on the form as follows:

   

   Control		(Name)	Other Properties
   ListView		lvwWaterMeters	FullRowSelect: True GridLines: True View: Details

9. Doubte-click an unoccupied area of the form to generate its Load event
10. Change the document as follows:

    using System.Text.Json;
    using StellarWaterPoint4.Models;
    
    namespace StellarWaterPoint4.WaterMeters
    {
        public partial class Central : Form
        {
            public Central()
            {
                InitializeComponent();
            }
    
            private void ShowWaterMeters()
            {
                string strWaterMeters = string.Empty;
                List<WaterMeter> waterMeters = new List<WaterMeter>();
                string fileWaterMeters = @"E:\Stellar Water Point2\WaterMeters.json";
    
                FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
    
                if (fiWaterMeters.Exists == true)
                {
                    using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                    {
                        strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                        waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
    
                        int counter = 1;
    
                        lvwWaterMeters.Items.Clear();
    
                        foreach (WaterMeter wm in waterMeters)
                        {
                            ListViewItem lviWaterMeter = new ListViewItem(counter++.ToString());
    
                            lviWaterMeter.SubItems.Add(wm.MeterNumber);
                            lviWaterMeter.SubItems.Add(wm.Make);
                            lviWaterMeter.SubItems.Add(wm.Model);
                            lviWaterMeter.SubItems.Add(wm.MeterSize);
    
                            lvwWaterMeters.Items.Add(lviWaterMeter);
                        }
                    }
                }
            }
    
            private void Central_Load(object sender, EventArgs e)
            {
                ShowWaterMeters();
            }
        }
    }

11. In the Solution Explorer, double-click WaterDistribution.cs to display the main form of the application
12. From the Toolbox, add a button to the form
13. From the Properties window, change the characteristics of the button as follows:

    

    Control		(Name)	Text	Font
    Button		btnWaterMeters	&Water Meters...	Times New Roman, 24pt, style=Bold

14. Double-click the &Water Meters button
15. Impliment the event as follows:

    namespace StellarWaterPoint3
    {
        public partial class WaterDistribution : Form
        {
            public WaterDistribution()
            {
                InitializeComponent();
            }
    
            private void btnWaterMeters_Click(object sender, EventArgs e)
            {
                WaterMeters.Central central = new WaterMeters.Central();
    
                central.ShowDialog();
            }
        }
    }

A Water Meter Record

.

Practical Learning: Creating a Water Meter Record

1. To create a form, in the Solution Explorer, right-click the WaterMeters folder -> Add -> Form (Windows Forms)...
2. Type Create
3. Design the form as follows:

   

   Control		(Name)	Text	Other Properties
   Label			&Meter #:
   MaskedTextBox		mtbMeterNumber		Masked: 000-000-000
   Label			M&ake:
   TextBox		txtMake		Modifiers: Public
   Label			M&odel:
   TextBox		txtModel		Modifiers: Public
   Label			Me&ter Size:
   TextBox		txtMeterSize		Modifiers: Public
   Button		btnOK	&OK	DialogResult: OK
   Button		btnCancel	&Cancel	DialogResult: Cancel

4. Using the Properties window, change some characteristics of the form as follows:

   FormBorderStyle: FixedDialog
   Text:            Stellar Water Point - Water Meter Setup
   StartPosition:   CenterScreen
   AcceptButton:    btnOK
   CancelButton:    btnCancel

5. In the Solution Explorer, below the WaterMeters folder, double-click Central.cs
6. From the Toolbox, add a button to the form below the list view
7. Change the characteristics of the button as follows:

   

   Control		(Name)	Other Properties
   ListView		No Change	No Change
   Button		btnNewWaterMeter	Text: &New Water Meter...

8. On the Central form, double-click the New Water Meter button
9. Implement the event as follows:

   using System.Text.Json;
   using StellarWaterPoint4.Models;
   
   namespace StellarWaterPoint4.WaterMeters
   {
       public partial class Central : Form
       {
           public Central()
           {
               InitializeComponent();
           }
   
           private void ShowWaterMeters()
           {
               . . .
           }
   
           private void Central_Load(object sender, EventArgs e)
           {
               ShowWaterMeters();
           }
   
           private void btnNewWaterMeter_Click(object sender, EventArgs e)
           {
               Create create = new();
   
               if (create.ShowDialog() == DialogResult.OK)
               {
                   if (string.IsNullOrEmpty(create.mtbMeterNumber.Text))
                   {
                       MessageBox.Show("You must type a meter number. " +
                                       "Otherwise, the water meter cannot be set up.",
                                       "Stellar Water Point", MessageBoxButtons.OK);
                       return;
                   }
   
                   string strWaterMeters = string.Empty;
                   List<WaterMeter> waterMeters = new List<WaterMeter>();
                   string fileWaterMeters = @"E:\Stellar Water Point2\WaterMeters.json";
   
                   FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
   
                   if (fiWaterMeters.Exists == true)
                   {
                       strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                       waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
                   }
   
                   WaterMeter wm = new WaterMeter()
                   {
                       MeterNumber = create.mtbMeterNumber.Text,
                       Make = create.txtMake.Text,
                       Model = create.txtModel.Text,
                       MeterSize = create.txtMeterSize.Text
                   };
   
                   waterMeters.Add(wm);
   
                   JsonSerializerOptions options = new JsonSerializerOptions();
                   options.WriteIndented = true;
   
                   string jsWaterMeters = JsonSerializer.Serialize(waterMeters, typeof(List<WaterMeter>), options);
                   File.WriteAllText(fiWaterMeters.FullName, jsWaterMeters);
               }
   
               ShowWaterMeters();
           }
       }
   }

10. To execute the application, on the main menu, click Debug -> Start Without Debugging

    

11. On the Central form, click the Water Meters button:

    

12. Click the New Water Meter button:

    

13. Enter the value for each of the following records and click OK (or press Enter) for each:

    Meter #	Make	Model	Meter Size
    392-494-572	Constance Technologies	TG-4822	5/8 Inches
    938-705-869	Stan Wood	66-G	1 Inch
    588-279-663	Estellano	NCF-226	3/4 Inches

    

14. Close the forms and return to your programming environment
15. In the Solution Explorer, double-click WaterDistribution.cs to access the primary form of the application
16. Double-click an unoccupied area of the form to access its code
17. Comment the call of the AccountType class as follows:

    using StellarWaterPoint4.Models;
    
    namespace StellarWaterPoint4
    {
        public partial class WaterDistribution : Form
        {
            public WaterDistribution()
            {
                InitializeComponent();
            }
    
            private void WaterDistribution_Load(object sender, EventArgs e)
            {
                Directory.CreateDirectory(@"E:\Stellar Water Point2");
    
                // Repository.CreateAccountsTypes();
            }
    
            private void btnWaterMeters_Click(object sender, EventArgs e)
            {
                WaterMeters.Central central = new();
    
                central.Show();
            }
        }
    }

Water Meter Details

.

Practical Learning: Creating a Water Meter Record

1. To create a form, in the Solution Explorer, right-click WaterMeters -> Add -> Form (Windows Forms)...
2. For the Name of the form, type Details
3. Press Enter
4. Design the form as follows:

   

   Control		(Name)	Text	Enabled	Modifiers	Other Properties
   Label			&Meter #:
   MaskedTextBox		mtbMeterNumber		False	Public	Masked: 000-000-000
   Button		btnFindWaterMeter	&Find Water Meter
   Label			Make:
   TextBox		txtMake		False	Public
   Label			Model:
   TextBox		txtModel		False	Public
   Label			Meter Size:
   TextBox		txtMeterSize		False	Public
   Button		btnClose	&Close

5. On the form, double-click the Find Water Meter button
6. Return to the form and double-click the Close button
7. Change the document as follows:

   using System.Text.Json;
   using StellarWaterPoint4.Models;
   
   namespace StellarWaterPoint4.WaterMeters
   {
       public partial class Details : Form
       {
           public Details()
           {
               InitializeComponent();
           }
   
           private void btnFindWateMeter_Click(object sender, EventArgs e)
           {
               if (string.IsNullOrEmpty(mtbMeterNumber.Text))
               {
                   MessageBox.Show("You must type a valid meter number, " +
                                   "and then click the Find Water Meter button.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
   
               string strWaterMeters = string.Empty;
               List<WaterMeter> waterMeters = new List<WaterMeter>();
               string fileWaterMeters = @"E:\Stellar Water Point2\WaterMeters.json";
   
               FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
   
               if (fiWaterMeters.Exists == true)
               {
                   strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                   waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
   
                   foreach (WaterMeter meter in waterMeters)
                   {
                       if (meter.MeterNumber == mtbMeterNumber.Text)
                       {
                           txtMake.Text = meter.Make;
                           txtModel.Text = meter.Model;
                           txtMeterSize.Text = meter.MeterSize;
                       }
                   }
               }
           }
   
           private void btnClose_Click(object sender, EventArgs e)
           {
               Close();
           }
       }
   }

8. In the Solution Explorer, below the WaterMeters folder, double-click Central.cs to open its form
9. From the Toolbox, add a button to the form below the list view and to the right of the New Water Meter button
10. Change the characteristics of the button as follows:

    

    Control		(Name)	Other Properties
    ListView		No Change	No Change
    Button		No Change	No Change
    Button		btnViewWaterMeter	&View Water Meter...

11. Double-click the View Water Meter button
12. Change the document as follows:

    using System.Data;
    using System.json;
    using Microsoft.Data.SqlClient;
    
    namespace StellarWaterPoint30.WaterMeters
    {
        public partial class Central : Form
        {
            public Central()
            {
                InitializeComponent();
            }
    
            private void ShowWaterMeters()
            {
                . . .
            }
    
            private void Central_Load(object sender, EventArgs e)
            {
                ShowWaterMeters();
            }
    
            private void btnNewWaterMeter_Click(object sender, EventArgs e)
            {
                . . .
            }
    
            private void lvwWaterMeters_DoubleClick(object sender, EventArgs e)
            {
                . . .
            }
    
    
            private void btnViewWaterMeter_Click(object sender, EventArgs e)
            {
                Details view = new();
                
                view.ShowDialog();
                
                ShowWaterMeters();
            }
        }
    }

13. To execute the application, on the main menu, click Debug -> Start Without Debugging

    

14. On the Water Distribution form, click the Water Meters button
15. On the Central form of water meters, click the View Water Meter button:

    

16. In the Meter # text, type 392-494-572
17. Click the Find Water Button button:

    

18. Close the Details form
19. On the Water Meters form, double-click the third record
20. Close the forms and return to your programming environment

Updating a Water Meter Details

One of the routine operations performed on a database is to change the details of a record. To support this operation for a water meter, we will create a form that can be used to update the information of a water meter.

Practical Learning: Updating a Water Meter

1. To create a form, in the Solution Explorer, right-click WaterMeters -> Add -> Form (Windows Forms)...
2. For the Name of the file, type Editor as the name of the form
3. Click Add
4. Design the form as follows:

   

   Control		(Name)	Text	Enabled	Other Properties
   Label			&Meter #:
   MaskedTextBox		mtbMeterNumber		False	Masked: 000-000-000
   Button		btnFindWaterMeter	&Find Water Meter
   Label			Make:
   TextBox		txtMake		False
   Label			Model:
   TextBox		txtModel		False
   Label			Meter Size:
   TextBox		txtMeterSize		False
   Button		btnFindWateMeter	&Find Wate Meter
   Button		btnClose	&Close

5. On the form, double-click the Find Water Meter button
6. Change the document as follows:

   using System.Text.Json;
   using StellarWaterPoint4.Models;
   
   namespace StellarWaterPoint4.WaterMeters
   {
       public partial class Editor : Form
       {
           public Editor()
           {
               InitializeComponent();
           }
   
           private void btnFindWateMeter_Click(object sender, EventArgs e)
           {
               if (string.IsNullOrEmpty(mtbMeterNumber.Text))
               {
                   MessageBox.Show("You must type a valid meter number, " +
                                   "and then click the Find Water Meter button.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
   
               string strWaterMeters = string.Empty;
               List<WaterMeter> waterMeters = new List<WaterMeter>();
               string fileWaterMeters = @"E:\Stellar Water Point2\WaterMeters.json";
   
               FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
   
               if (fiWaterMeters.Exists == true)
               {
                   strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                   waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
   
                   WaterMeter meter = waterMeters.Find(mtr => mtr.MeterNumber == mtbMeterNumber.Text)!;
   
                   txtMake.Text = meter.Make;
                   txtModel.Text = meter.Model;
                   txtMeterSize.Text = meter.MeterSize;
               }
           }    
       }
   }

7. Return to the form and double-click the Update Water Meter button
8. Return to the form and double-click the Close button
9. Change the document as follows:

   using System.Text.Json;
   using StellarWaterPoint4.Models;
   
   namespace StellarWaterPoint4.WaterMeters
   {
       public partial class Editor : Form
       {
           public Editor()
           {
               InitializeComponent();
           }
   
           private void btnFindWateMeter_Click(object sender, EventArgs e)
           {
               if (string.IsNullOrEmpty(mtbMeterNumber.Text))
               {
                   MessageBox.Show("You must type a valid meter number, " +
                                   "and then click the Find Water Meter button.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
   
               string strWaterMeters = string.Empty;
               List<WaterMeter> waterMeters = new List<WaterMeter>();
               string fileWaterMeters = @"E:\Stellar Water Point2\WaterMeters.json";
   
               FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
   
               if (fiWaterMeters.Exists == true)
               {
                   strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                   waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
   
                   WaterMeter meter = waterMeters.Find(mtr => mtr.MeterNumber == mtbMeterNumber.Text)!;
   
                   txtMake.Text = meter.Make;
                   txtModel.Text = meter.Model;
                   txtMeterSize.Text = meter.MeterSize;
               }
           }
   
           private void btnUpdateWaterMeter_Click(object sender, EventArgs e)
           {
               if (string.IsNullOrEmpty(mtbMeterNumber.Text))
               {
                   MessageBox.Show("You must type a valid meter number, " +
                                   "and then click the Find Water Meter button.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
   
               string strWaterMeters = string.Empty;
               List<WaterMeter> waterMeters = new List<WaterMeter>();
               string fileWaterMeters = @"E:\Stellar Water Point2\WaterMeters.json";
   
               FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
   
               if (fiWaterMeters.Exists == true)
               {
                   strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                   waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
   
                   WaterMeter? meter = waterMeters.Find(mtr => mtr.MeterNumber == mtbMeterNumber.Text);
   
                   if (meter is not null)
                   {
                       meter.Make = txtMake.Text;
                       meter.Model = txtModel.Text;
                       meter.MeterSize = txtMeterSize.Text;
   
                       JsonSerializerOptions options = new JsonSerializerOptions();
                       options.WriteIndented = true;
   
                       string jsWaterMeters = JsonSerializer.Serialize(waterMeters, typeof(List<WaterMeter>), options);
                       File.WriteAllText(fiWaterMeters.FullName, jsWaterMeters);
                   }
               }
   
               Close();
           }
   
           private void btnClose_Click(object sender, EventArgs e)
           {
               Close();
           }
       }
   }

10. In the Solution Explorer, below the WaterMeters folder, double-click Central.cs
11. From the Toolbox, add a button to the form below the list view and on the right side of the View Water Meter button
12. Change the characteristics of the button as follows:

    

    Control		(Name)	Other Properties
    ListView		No Change	No Change
    Button		No Change	No Change
    Button		No Change	No Change
    Button		btnEditWaterMeter	&Edit Water Meter... Anchor: Bottom, Right

13. Display the Central form of the WaterMeters folder
14. Double-click the Update Water Meter button
15. Change the document as follows:

    using System.Text.Json;
    using StellarWaterPoint4.Models;
    
    namespace StellarWaterPoint4.WaterMeters
    {
        public partial class Central : Form
        {
            public Central()
            {
                InitializeComponent();
            }
    
            private void ShowWaterMeters()
            {
                . . .
            }
    
            private void Central_Load(object sender, EventArgs e)
            {
                ShowWaterMeters();
            }
    
            private void btnNewWaterMeter_Click(object sender, EventArgs e)
            {
                . . .
            }
    
            private void btnViewWaterMeter_Click(object sender, EventArgs e)
            {
                Details view = new();
    
                view.ShowDialog();
    
                ShowWaterMeters();
            }
    
            private void btnEditWaterMeter_Click(object sender, EventArgs e)
            {
                Editor editor = new();
    
                editor.ShowDialog();
    
                ShowWaterMeters();
            }
        }
    }

16. To execute the application, on the main menu, click Debug -> Start Without Debugging
17. On the Central form, click the Water Meters button
18. Click the Edit Water Meter button:

    

19. In the Meter # text, type 938-705-869
20. Click the Find button

    

21. Change the values as follows:

    Make:	Stanford Trend
    Model:	266G
    Meter Size:	1 1/2 Inches

    

22. Click the Update button:

    

23. Close the forms and return to your programming environment

Removing a Water Meter from the Database

If a record is not necessary anymore on a database, the user may want to remove it. To assist the user with this operation, we will create a form withe necessary buttons.

Practical Learning: Deleting a Water Meter Record

1. To create a form, in the Solution Explorer, right-click WaterMeters -> Add -> Form(Windows Forms)...
2. In the Name text box, replace the string with Delete as the name of the form
3. Press Enter
4. Design the form as follows:

   

   Control		(Name)	Text	Enabled	Other Properties
   Label			&Meter #:
   MaskedTextBox		mtbMeterNumber		False	Masked: 000-000-000
   Label			Make:
   TextBox		txtMake		False
   Label			Model:
   TextBox		txtModel		False
   Label			Meter Size:
   TextBox		txtMeterSize		False
   Button		btnClose	&Close

5. On the form, double-click the Find Water Meter button
6. Change the document as tollows:

   using System.Data;
   using Microsoft.Data.SqlClient;
   
   namespace StellarWaterPoint30.WaterMeters
   {
       public partial class Delete : Form
       {
           public Delete()
           {
               InitializeComponent();
           }
   
           private void btnFindWateMeter_Click(object sender, EventArgs e)
           {
               using (SqlConnection scWaterDistribution = new SqlConnection("Data Source=(local);" +
                                                                            "Initial Catalog='StellarWaterPoint30';" +
                                                                            "TrustServerCertificate=True;" +
                                                                            "Integrated Security=True;"))
               {
                   SqlCommand cmdWaterMeters = new SqlCommand("SELECT Make,           " +
                                                              "       Model,          " +
                                                              "       MeterSize       " +
                                                              "FROM   Management.WaterMeters " +
                                                              "WHERE  MeterNumber = N'" + mtbMeterNumber.Text + "';",
                                                              scWaterDistribution);
   
                   scWaterDistribution.Open();
   
                   SqlDataAdapter sdaWaterMeters = new SqlDataAdapter(cmdWaterMeters);
   
                   DataSet dsWaterMeters = new("WaterMetersSet");
                   sdaWaterMeters.Fill(dsWaterMeters);
   
                   foreach (DataRow drWaterMeter in dsWaterMeters.Tables[0].Rows!)
                   {
                       txtMake.Text = drWaterMeter[0].ToString();
                       txtModel.Text = drWaterMeter[1].ToString();
                       txtMeterSize.Text = drWaterMeter[2].ToString();
                   }
               }
           }
       }
   }

7. Return to the form and double-click the Delete Water Meter button
8. Return to the form and double-click the Close button
9. Change the document as tollows:

   using System.Text.Json;
   using StellarWaterPoint4.Models;
   
   namespace StellarWaterPoint4.WaterMeters
   {
       public partial class Delete : Form
       {
           public Delete()
           {
               InitializeComponent();
           }
   
           private void btnFindWateMeter_Click(object sender, EventArgs e)
           {
               if (string.IsNullOrEmpty(mtbMeterNumber.Text))
               {
                   MessageBox.Show("You must type a valid meter number, " +
                                   "and then click the Find Water Meter button.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
   
               string strWaterMeters = string.Empty;
               List<WaterMeter> waterMeters = new List<WaterMeter>();
               string fileWaterMeters = @"E:\Stellar Water Point2\WaterMeters.json";
   
               FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
   
               if (fiWaterMeters.Exists == true)
               {
                   strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                   waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
   
                   WaterMeter meter = waterMeters.Find(mtr => mtr.MeterNumber == mtbMeterNumber.Text)!;
   
                   txtMake.Text = meter.Make;
                   txtModel.Text = meter.Model;
                   txtMeterSize.Text = meter.MeterSize;
               }
           }
   
           private void btnDeleteWaterMeter_Click(object sender, EventArgs e)
           {
               if (string.IsNullOrEmpty(mtbMeterNumber.Text))
               {
                   MessageBox.Show("You must type a valid meter number, " +
                                   "and then click the Find Water Meter button.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
   
               string strWaterMeters = string.Empty;
               List<WaterMeter> waterMeters = new List<WaterMeter>();
               string fileWaterMeters = @"E:\Stellar Water Point2\WaterMeters.json";
   
               FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
   
               if (fiWaterMeters.Exists == true)
               {
                   strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                   waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
   
                   WaterMeter meter = waterMeters.Find(mtr => mtr.MeterNumber == mtbMeterNumber.Text)!;
   
                   if (meter is not null)
                   {
                       if (MessageBox.Show("Are you sure you want to delete this water meter " +
                                         "(you cannot undo the action)?",
                                         "Stellar Water Point", MessageBoxButtons.YesNo, MessageBoxIcon.Information) == DialogResult.Yes)
                       {
                           waterMeters.Remove(meter);
   
                           JsonSerializerOptions options = new JsonSerializerOptions();
                           options.WriteIndented = true;
   
                           string jsWaterMeters = JsonSerializer.Serialize(waterMeters, typeof(List<WaterMeter>), options);
                           File.WriteAllText(fiWaterMeters.FullName, jsWaterMeters);
   
                           MessageBox.Show("The water meter has been removed from our database.",
                                         "Stellar Water Point", MessageBoxButtons.OK, MessageBoxIcon.Information);
                       }
                   }
               }
   
               Close();
           }
   
           private void btnClose_Click(object sender, EventArgs e)
           {
               Close();
           }
       }
   }

10. In the Solution Explorer, below the WaterMeters folder, double-click Central.cs
11. From the Toolbox, add two buttons to the form below the list view and on the right side of the Edit Water Meter button
12. Change the characteristics of the buttons as follows:

    

    Control		(Name)	Text	Anchor
    ListView		lvwWaterMeters		Top, Bottom, Left, Right
    Button		btnNewWaterMeter	&New Water Meter...	Bottom, Right
    Button		btnViewWaterMeter	&View Water Meter...	Bottom, Right
    Button		btnEditWaterMeter	&Edit Water Meter...	Bottom, Right
    Button		btnDeleteWateMeter	&Delete Water Meter...	Bottom, Right
    Button		btnClose	&Close	Bottom, Right

13. On the form, double-click the Delete Water Meter button
14. Return to the Central form of the water meters and double-click the Close button
15. Change the document as follows:

    using System.Text.Json;
    using StellarWaterPoint4.Models;
    
    namespace StellarWaterPoint4.WaterMeters
    {
        public partial class Central : Form
        {
            public Central()
            {
                InitializeComponent();
            }
    
            private void ShowWaterMeters()
            {
                string strWaterMeters = string.Empty;
                List<WaterMeter> waterMeters = new List<WaterMeter>();
                string fileWaterMeters = @"E:\Stellar Water Point2\WaterMeters.json";
    
                FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
    
                if (fiWaterMeters.Exists == true)
                {
                    using (TextReader trWaterMeters = new StreamReader(fiWaterMeters.FullName))
                    {
                        strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                        waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
    
                        int counter = 1;
    
                        lvwWaterMeters.Items.Clear();
    
                        foreach (WaterMeter meter in waterMeters)
                        {
                            ListViewItem lviWaterMeter = new ListViewItem(counter++.ToString());
    
                            lviWaterMeter.SubItems.Add(meter.MeterNumber);
                            lviWaterMeter.SubItems.Add(meter.Make);
                            lviWaterMeter.SubItems.Add(meter.Model);
                            lviWaterMeter.SubItems.Add(meter.MeterSize);
    
                            lvwWaterMeters.Items.Add(lviWaterMeter);
                        }
                    }
                }
            }
    
            private void Central_Load(object sender, EventArgs e)
            {
                ShowWaterMeters();
            }
    
            private void btnNewWaterMeter_Click(object sender, EventArgs e)
            {
                Create create = new();
    
                if (create.ShowDialog() == DialogResult.OK)
                {
                    if (string.IsNullOrEmpty(create.mtbMeterNumber.Text))
                    {
                        MessageBox.Show("You must type a meter number. " +
                                        "Otherwise, the water meter cannot be set up.",
                                        "Stellar Water Point", MessageBoxButtons.OK);
                        return;
                    }
    
                    string strWaterMeters = string.Empty;
                    List<WaterMeter> waterMeters = new List<WaterMeter>();
                    string fileWaterMeters = @"E:\Stellar Water Point2\WaterMeters.json";
    
                    FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
    
                    if (fiWaterMeters.Exists == true)
                    {
                        strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                        waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
                    }
    
                    WaterMeter meter = new WaterMeter()
                    {
                        MeterNumber = create.mtbMeterNumber.Text,
                        Make = create.txtMake.Text,
                        Model = create.txtModel.Text,
                        MeterSize = create.txtMeterSize.Text
                    };
    
                    waterMeters.Add(meter);
    
                    JsonSerializerOptions options = new JsonSerializerOptions();
                    options.WriteIndented = true;
    
                    string jsWaterMeters = JsonSerializer.Serialize(waterMeters, typeof(List<WaterMeter>), options);
                    File.WriteAllText(fiWaterMeters.FullName, jsWaterMeters);
                }
    
                ShowWaterMeters();
            }
    
            private void btnViewWaterMeter_Click(object sender, EventArgs e)
            {
                Details view = new();
    
                view.ShowDialog();
    
                ShowWaterMeters();
            }
    
            private void btnEditWaterMeter_Click(object sender, EventArgs e)
            {
                Editor editor = new();
    
                editor.ShowDialog();
    
                ShowWaterMeters();
            }
    
            private void btnDeleteWateMeter_Click(object sender, EventArgs e)
            {
                Delete delete = new();
    
                delete.ShowDialog();
    
                ShowWaterMeters();
            }
    
            private void btnClose_Click(object sender, EventArgs e)
            {
                Close();
            }
        }
    }

16. To execute the application, on the main menu, click Debug -> Start Without Debugging:

    

17. On the Central form, click the Water Meters button:

    

18. On the Central form of the water meters, click the Delete Water Meter button:

    

19. In the Meter # text, type 588-279-663
20. Click the Find button:

    

21. Click the Delete button:

    

22. Read the text on the message box:

    

    On the message box, click Yes

    

23. In the same way, delete the other two records
24. Close the forms and return to your programming environment
25. In the Colution Eplorer, below Models, double-click Repository.cs to open its class
26. In the Repository class, add the following method:

    using StellarWaterPoint4.WaterMeters;
    using System.Text.Json;
    
    namespace StellarWaterPoint4.Models
    {
        public static class Repository
        {
            public static void CreateWaterMeters()
            {
                List<WaterMeter> waterMeters = new List<WaterMeter>();
    
                waterMeters!.Add(new WaterMeter() { MeterNumber = "392-494-572", Make = "Constance Technologies", Model = "TG-4822", MeterSize = "5/8 Inches" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "938-725-869", Make = "Stanford Trend", Model = "266G", MeterSize = "1 1/2 Inches" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "588-279-663", Make = "Estellano", Model = "NCF-226", MeterSize = "4 Inches" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "186-962-805", Make = "Lansome", Model = "2800", MeterSize = "1 1/2 Inches" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "379-386-979", Make = "Planetra", Model = "P-2020", MeterSize = "4 Inches" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "580-742-825", Make = "Kensa Sons", Model = "KS2000A", MeterSize = "1 3/4 Inches" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "849-351-444", Make = "Raynes Energica", Model = "a1088", MeterSize = "2 Inches" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "208-428-308", Make = "Constance Technologies", Model = "808D", MeterSize = "3/4 Inches" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "738-588-249", Make = "Warrington", Model = "W4242", MeterSize = "5/8 Inches" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "496-813-794", Make = "Estellano", Model = "NCF-226", MeterSize = "3/4 Inches" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "862-715-006", Make = "Warrington", Model = "W-4040", MeterSize = "1/2 Inch" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "649-358-184", Make = "Raynes Energica", Model = "b1700", MeterSize = "1 1/2 Inches" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "928-317-924", Make = "Gongola", Model = "GN1000", MeterSize = "2 Inch" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "595-753-147", Make = "Grass Grill", Model = "CRC-1000", MeterSize = "1 Inch" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "799-528-461", Make = "Kensa Sons", Model = "K-584-L", MeterSize = "3/4 Inches" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "386-468-057", Make = "Estellano", Model = "NCF-226", MeterSize = "3/4 Inches" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "938-275-294", Make = "Constance Technologies", Model = "TT-8822", MeterSize = "4 Inches" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "288-427-585", Make = "Planetra", Model = "P-2020", MeterSize = "1/2 Inch" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "394-835-297", Make = "Raynes Energica", Model = "i2022", MeterSize = "3/4 Inches" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "847-252-246", Make = "Master Stream", Model = "2000-MS", MeterSize = "1 1/2 Inches" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "349-725-848", Make = "Planetra", Model = "P-8000", MeterSize = "4 Inches" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "713-942-058", Make = "Master Stream", Model = "3366-MS", MeterSize = "3/4 Inches" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "747-581-379", Make = "Warrington", Model = "W4242", MeterSize = "5/8 Inches" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "582-755-263", Make = "Kensa Sons", Model = "KS2000A", MeterSize = "1 Inch" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "827-260-758", Make = "Raynes Energica", Model = "a1088", MeterSize = "1-1/4 Inch" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "837-806-836", Make = "Lansome", Model = "7400", MeterSize = "5/8 Inches" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "207-964-835", Make = "Constance Technologies", Model = "TG-6220", MeterSize = "5/8 Inches" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "296-837-495", Make = "Raynes Energica", Model = "QG505", MeterSize = "4 Inches" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "468-359-486", Make = "Grass Grill", Model = "KLP-8822", MeterSize = "1-1/4 Inch" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "931-486-003", Make = "Planetra", Model = "P-2020", MeterSize = "1/2 Inch" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "483-770-648", Make = "Warren", Model = "WWW", MeterSize = "0.1 Inches" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "592-824-957", Make = "Kensa Sons", Model = "D-497-H", MeterSize = "3/4 Inches" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "293-835-704", Make = "Gongola", Model = "GOL1000", MeterSize = "1/2 Inch" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "739-777-749", Make = "Warrington", Model = "W2200W", MeterSize = "3/4 Inches" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "374-886-284", Make = "Raynes Energica", Model = "i2022", MeterSize = "3/4 Inches" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "186-959-757", Make = "Kensa Sons", Model = "M-686-G", MeterSize = "1 1/2 Inches" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "594-827-359", Make = "Planetra", Model = "P-8000", MeterSize = "1 Inch" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "394-739-242", Make = "Master Stream", Model = "9393-TT", MeterSize = "5/8 Inches" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "529-283-752", Make = "Constance Technologies", Model = "404T", MeterSize = "3/4 Inches" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "295-770-695", Make = "Warrington", Model = "W-2286", MeterSize = "1-1/4 Inch" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "739-749-737", Make = "Kensa Sons", Model = "KS2000A", MeterSize = "1 Inch" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "947-528-317", Make = "Gondola", Model = "GDL-5000", MeterSize = "1 Inch" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "630-207-055", Make = "Lansome", Model = "2800", MeterSize = "3/4 Inches" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "827-508-248", Make = "Standard Trend", Model = "428T", MeterSize = "3/4 Inches" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "293-924-869", Make = "Grass Grill", Model = "CRC-2020", MeterSize = "1/2 Inch" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "928-247-580", Make = "Gondola", Model = "GOL2000", MeterSize = "0.34 Inch" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "682-537-380", Make = "Planetra", Model = "P-2020", MeterSize = "1-1/4 Inch" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "470-628-850", Make = "Estellano", Model = "WRT-482", MeterSize = "3/4 Inches" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "649-373-505", Make = "Constance Technologies", Model = "BD-7000", MeterSize = "5/8 Inches" });
                waterMeters.Add(new WaterMeter()  { MeterNumber = "306-842-497", Make = "Lansome", Model = "9000", MeterSize = "3/4 Inches" });
    
                string strWaterMeters         = string.Empty;
                string fileWaterMeters        = @"E:\Stellar Water Point2\WaterMeters.json";
    
                JsonSerializerOptions options = new JsonSerializerOptions();
                options.WriteIndented         = true;
    
                FileInfo fiWaterMeters        = new FileInfo(fileWaterMeters);
                string jsWaterMeters          = JsonSerializer.Serialize(waterMeters, typeof(List<WaterMeter>), options);
                File.WriteAllText(fiWaterMeters.FullName, jsWaterMeters);
            }
        }
    }

27. In the Solution Explorer, double-click WaterDistribution.cs
28. Double-click an unoccupied area of the form
29. Class the function as follows:

    using StellarWaterPoint4.Models;
    
    namespace StellarWaterPoint4
    {
        public partial class WaterDistribution : Form
        {
            public WaterDistribution()
            {
                InitializeComponent();
            }
    
            private void WaterDistribution_Load(object sender, EventArgs e)
            {
                Directory.CreateDirectory(@"E:\Stellar Water Point2");
    
                // Repository.CreateAccountsTypes();
                Repository.CreateWaterMeters();
            }
    
            private void btnWaterMeters_Click(object sender, EventArgs e)
            {
                WaterMeters.Central central = new();
    
                central.Show();
            }
        }
    }

30. To execute the application, on the main menu, click Debug -> Start Without Debugging
31. Close the forms and return to your programming environment

Customers

Introduction

.

Practical Learning: Introducing Customers

1. To create a class, in the Solution Explorer, right-click Models -> Add -> Class...
2. On the main menu, click Project -> Add Class...
3. Replace the name with Customer
4. Click Add
5. Change the code as follows:

   namespace StellarWaterPoint4.Models
   {
       public class Customer
       {
           public string? AccountNumber { get; set; }
           public string? AccountName   { get; set; }
           public string? MeterNumber   { get; set; }
           public string? AccountType   { get; set; }
           public string? Address       { get; set; }
           public string? City          { get; set; }
           public string? County        { get; set; }
           public string? State         { get; set; }
           public string? ZIPCode       { get; set; }
       }
   }

6. To create a folder, in the Solution Explorer, right-click the StellarWaterPoint4 project -> Add -> New Folder
7. Type Customers as the name of the folder

Displaying Customers

.

Practical Learning: Displaying Customers

1. To create a form, in the Solution Explorer, right-click Customers -> Add -> Form (Windows Forms)...
2. For the Name of the form, type Central
3. Click Add
4. In the Toolbox, click the ListView button and click the form
5. On the form, right-click the list view and click Edit Columns...
6. Create the columns as follows:

   (Name)	Text	TextAlign	Width
   colCustomerId	Id		40
   colAccountNumber	Account #	Center	150
   colAccountName	Account Name		200
   colMeterNumber	Meter #	Center	100
   colAccountType	Account Type		200
   colAddress	Address		250
   colCity	City		125
   colCounty	County		125
   colState	State	Center
   colZIPCode	ZIP-Code	Center	125

7. Click OK
8. Position and resize the list view on the form as follows:

   

   Control		(Name)	Other Properties
   ListView		lvwCustomers	FullRowSelect: True GridLines: True View: Details

9. Double-click an unoccupied area of the form to generate its Load event
10. Change the document as follows:

    using StellarWaterPoint4.Models;
    using System.Text.Json;
    
    namespace StellarWaterPoint4.Customers
    {
        public partial class Central : Form
        {
            public Central()
            {
                InitializeComponent();
            }
    
            private void ShowCustomers()
            {
                . . .
            }
    
            private void Central_Load(object sender, EventArgs e)
            {
                ShowCustomers();
            }
    
            private void btnCreateCustomerAccount_Click(object sender, EventArgs e)
            {
                Create create = new();
    
                create.ShowDialog();
    
                ShowCustomers();
            }
        }
    }

11. In the Solution Explorer, double-click WaterDistribution.cs to display the main form of the application
12. From the Toolbox, add a button to the form
13. From the Properties window, change the characteristics of the button as follows:

    

    Control		(Name)	Text	Font
    Button		btnCustomers	C&ustomers...	Times New Roman, 24pt, style=Bold

14. Double-click the C&ustomers
15. Impliment the event as follows:

    using StellarWaterPoint4.Models;
    
    namespace StellarWaterPoint4
    {
        public partial class WaterDistribution : Form
        {
            public WaterDistribution()
            {
                InitializeComponent();
            }
    
            private void WaterDistribution_Load(object sender, EventArgs e)
            {
                Directory.CreateDirectory(@"E:\Stellar Water Point2");
    
                // Repository.CreateAccountsTypes();
                // Repository.CreateWaterMeters();
            }
    
            private void btnCustomers_Click(object sender, EventArgs e)
            {
                Customers.Central central = new();
    
                central.Show();
            }
    
            private void btnWaterMeters_Click(object sender, EventArgs e)
            {
                WaterMeters.Central central = new();
    
                central.Show();
            }
        }
    }

A New Customer Account

.

Practical Learning: Creating a Customer Account

1. To create a form, in the Solution Explorer, right-click the WaterMeters folder -> Add -> Form (Windows Forms)...
2. For the Name of the file, type Create as the name of the form
3. Click Add
4. Design the form as follows:

   

   Control		(Name)	Text	Other Properties
   Label			&Account #:
   MaskedTextBox		mtbAccountNumber		Masked: 0000-000-0000
   Label			&Account Name:
   TextBox		txtAccountName
   Label			&Meter #:
   MaskedTextBox		mtbMeterNumber		Masked: 000-000-000
   Button		btnFindWaterMeter	&Find Water Meter
   Label			Meter &Details:
   TextBox		txtMeterDetails		Enabled: False
   Label			&Account Type:
   ComboBox		cbxAccountsTypes
   Label			&Address:
   TextBox		txtAddress
   Label			C&ity:
   TextBox		txtCity
   Label			C&ounty:
   TextBox		txtCounty
   Label			&State:
   TextBox		txtState
   Label			&ZIP-Code:
   MaskedTextBox		mtbZIPCode		Masked: Zip-Code
   Button		btnSaveCustomerAccount	S&ave Customer Account	DialogResult: OK
   Button		btnClose	&Close	DialogResult: Cancel

5. Using the Properties window, change some characteristics of the form as follows:

   FormBorderStyle: FixedDialog
   Text:            Stellar Water Point - Create Customer Account
   StartPosition:   CenterScreen
   AcceptButton:    btnCreateCustomerAccount
   CancelButton:    btnCancel

6. Double-click an unoccupied area of the form to generate its Load event
7. Change the document as follows:

   using System.Text.Json;
   using StellarWaterPoint4.Models;
   
   namespace StellarWaterPoint4.Customers
   {
       public partial class Create : Form
       {
           public Create()
           {
               InitializeComponent();
           }
   
           private void Create_Load(object sender, EventArgs e)
           {
               string strAccountsTypes    = string.Empty;
               List<AccountType> types    = new List<AccountType>();
               string fileAccountsTypes   = @"E:\Stellar Water Point2\AccountsTypes.json";
   
               FileInfo fiAccountsTypes   = new FileInfo(fileAccountsTypes);
   
               if (fiAccountsTypes.Exists == true)
               {
                   strAccountsTypes       = File.ReadAllText(fiAccountsTypes.FullName);
                   types = JsonSerializer.Deserialize<List<AccountType>>(strAccountsTypes)!;
   
                   foreach (AccountType type in types)
                   {
                       cbxAccountsTypes.Items.Add(type.TypeCode + " - " + type.TypeDecription);
                   }
               }
           }
       }
   }

8. Return to the form and double-click the Find Water Meter button
9. Implement the event as tollows:

   using System.Text.Json;
   using StellarWaterPoint4.Models;
   
   namespace StellarWaterPoint4.Customers
   {
       public partial class Create : Form
       {
           public Create()
           {
               InitializeComponent();
           }
   
           private void Create_Load(object sender, EventArgs e)
           {
               string strAccountsTypes = string.Empty;
               List<AccountType> types = new List<AccountType>();
               string fileAccountsTypes = @"E:\Stellar Water Point2\AccountsTypes.json";
   
               FileInfo fiAccountsTypes = new FileInfo(fileAccountsTypes);
   
               if (fiAccountsTypes.Exists == true)
               {
                   strAccountsTypes = File.ReadAllText(fiAccountsTypes.FullName);
                   types = JsonSerializer.Deserialize<List<AccountType>>(strAccountsTypes)!;
   
                   foreach (AccountType type in types)
                   {
                       cbxAccountsTypes.Items.Add(type.TypeCode + " - " + type.TypeDecription);
                   }
               }
           }
   
           private void btnFindWateMeter_Click(object sender, EventArgs e)
           {
               if (string.IsNullOrEmpty(mtbMeterNumber.Text))
               {
                   MessageBox.Show("You must type a valid meter number, " +
                                   "and then click the Find Water Meter button.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
   
               string strWaterMeters = string.Empty;
               List<WaterMeter> waterMeters = new List<WaterMeter>();
               string fileWaterMeters = @"E:\Stellar Water Point2\WaterMeters.json";
   
               FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
   
               if (fiWaterMeters.Exists == true)
               {
                   strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                   waterMeters    = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
   
                   foreach (WaterMeter meter in waterMeters)
                   {
                       if (meter.MeterNumber == mtbMeterNumber.Text)
                       {
                           txtMeterDetails.Text = meter.Make + " " + 
                                                  meter.Model + 
                                                  " (Meter Size: " + meter.MeterSize + ")";
                       }
                   }
               }
           }
       }
   }

10. In the Solution Explorer, below the Customers folder, double-click Central.cs
11. From the Toolbox, add a button to the form below the list view
12. Change the characteristics of the button as follows:

    

    Control		(Name)	Other Properties
    ListView		lvwCustomers	FullRowSelect: True GridLines: True View: Details
    Button		btnNewCustomerAccount	&New Customer Account...

13. On the Central form, double-click the New Customer Account button
14. Implement the event as follows:

    using StellarWaterPoint4.Models;
    using System.Text.Json;
    
    namespace StellarWaterPoint4.Customers
    {
        public partial class Central : Form
        {
            public Central()
            {
                InitializeComponent();
            }
    
            private void ShowCustomers()
            {
                . . .
            }
    
            private void Central_Load(object sender, EventArgs e)
            {
                ShowCustomers();
            }
    
            private void btnCreateCustomerAccount_Click(object sender, EventArgs e)
            {
                Create create = new();
    
                if (create.ShowDialog() == DialogResult.OK)
                {
                    if (string.IsNullOrEmpty(create.mtbAccountNumber.Text))
                    {
                        MessageBox.Show("You must provide an account number for a new customer. " +
                                        "Otherwise, the account cannot be created.",
                                        "Stellar Water Point", MessageBoxButtons.OK);
                        return;
                    }
    
                    if (string.IsNullOrEmpty(create.mtbMeterNumber.Text))
                    {
                        MessageBox.Show("You must type a valid meter number to associate " +
                                        "a water meter to a customer's account. After providing " +
                                        "a meter number, click the Find Water Meter button.",
                                        "Stellar Water Point", MessageBoxButtons.OK);
                        return;
                    }
    
                    string strCustomers    = string.Empty;
                    List<Customer> clients = new List<Customer>();
                    string fileCustomers   = @"E:\Stellar Water Point2\Customers.json";
    
                    FileInfo fiCustomers   = new FileInfo(fileCustomers);
    
                    if (fiCustomers.Exists == true)
                    {
                        strCustomers       = File.ReadAllText(fiCustomers.FullName);
                        clients            = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
                    }
    
                    Customer client        = new Customer()
                    {
                        AccountNumber      = create.mtbAccountNumber.Text,
                        AccountName        = create.txtAccountName.Text,
                        MeterNumber        = create.mtbMeterNumber.Text,
                        AccountType        = create.cbxAccountsTypes.Text,
                        Address            = create.txtAddress.Text,
                        City               = create.txtCity.Text,
                        County             = create.txtCounty.Text,
                        State              = create.txtState.Text,
                        ZIPCode            = create.mtbZIPCode.Text
                    };
    
                    clients.Add(client);
    
                    JsonSerializerOptions options = new JsonSerializerOptions();
                    options.WriteIndented = true;
    
                    string jsCustomers = JsonSerializer.Serialize(clients, typeof(List<Customer>), options);
                    File.WriteAllText(fiCustomers.FullName, jsCustomers);
                }
    
                ShowCustomers();
            }
        }
    }

15. To execute the application, on the main menu, click Debug -> Start Without Debugging:

    

16. On the Water Distribution form, click the Customers button:

    

17. On the Central form of the customers, click the Create Customer Account button:

    

18. In the account # text box, type 9279-570-8394
19. In the meter # text box, type 799-528-461
20. Click the Find water meter button
21. Enter the other values as follows:

    Account #:    9279-570-8394
    Account Name: Thomas Stones
    Meter #:      799-528-461
    Account Type: RES - Residential Household
    Address:      10252 Broward Ave #D4
    City:         Frederick
    County:       Frederick
    State:        MD
    ZIP-Code:     21703-4422

    

22. Click Save Customer Account
23. In the same way, create the following two records:

    Account #	Account Name	Meter #	Account Type	Address	City	County	State	ZIP-Code
    4086-938-4783	Hernola Dough	594-827-359	UUO - Unidentified or Unclassified Type of Organization	10 10 Hexagonal Drv	Winston	Yoke	Penn	11402-4411
    7080-583-5947	Sunny Yard	827-508-248	WAT - Water Intensive Business(Laudromat, Hair Salon, Restaurant, etc	663 Sherry Wood East Street	Shimpstown	Franklin	PA	17236-2626

    

24. Close the forms and return to your programming environment

Customer Account Details

.

Practical Learning: Showing Customer Account

1. To create a form, in the Solution Explorer, right-click Customers -> Add -> Form (Windows Forms)...
2. For the Name of the form, type Details
3. Press Enter
4. Design the form as follows:

   

   Control		(Name)	Text	Other Properties
   Label			&Account #:
   MaskedTextBox		mtbAccountNumber		Masked: 0000-000-0000
   Label			&Account Name:
   TextBox		txtAccountName		Enabled: False
   Label			Meter &Details:
   TextBox		txtMeterDetails		Enabled: False
   Label			&Account Type:
   TextBox		txtAccountsTypes		Enabled: False
   Label			&Address:
   TextBox		txtAddress		Enabled: False
   Label			C&ity:
   TextBox		txtCity		Enabled: False
   Label			C&ounty:
   TextBox		txtCounty		Enabled: False
   Label			&State:
   TextBox		txtState		Enabled: False
   Label			&ZIP-Code:
   TextBox		txtZIPCode		Enabled: False
   Button		btnClose	&Close

5. On the form, double-click the Find Customer Account button
6. Return to the form and double-click the Close button
7. Change the document as follows:

   using StellarWaterPoint4.Models;
   using System.Text.Json;
   
   namespace StellarWaterPoint4.Customers
   {
       public partial class Details : Form
       {
           public Details()
           {
               InitializeComponent();
           }
   
           private void btnFindCustomerAccount_Click(object sender, EventArgs e)
           {
               
               if (string.IsNullOrEmpty(mtbAccountNumber.Text))
               {
                   MessageBox.Show("You must type a valid account number of a customer, " +
                                   "and then click the Find Customer Account button.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
   
               string strCustomers = string.Empty;
               List<Customer> clients = new List<Customer>();
               string fileCustomers = @"E:\Stellar Water Point2\Customers.json";
   
               FileInfo fiCustomers = new FileInfo(fileCustomers);
   
               string? strMeterNumber = string.Empty;
   
               if (fiCustomers.Exists == true)
               {
                   using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                   {
                       strCustomers = File.ReadAllText(fiCustomers.FullName);
                       clients = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
   
                       IEnumerable<Customer> customers = from   consumer
                                                         in     clients
                                                         where  consumer.AccountNumber == mtbAccountNumber.Text
                                                         select consumer;
   
                       foreach (Customer client in customers)
                       {
                           txtAccountName.Text = client.AccountName;
                           strMeterNumber      = client.MeterNumber;
                           txtAccountType.Text = client.AccountType;
                           txtAddress.Text     = client.Address;
                           txtCity.Text        = client.City;
                           txtCounty.Text      = client.County;
                           txtState.Text       = client.State;
                           txtZIPCode.Text     = client.ZIPCode;
                       }
                   }
               }
   
               if (strMeterNumber!.Length > 0)
               {
                   string strWaterMeters = string.Empty;
                   List<WaterMeter> waterMeters = new List<WaterMeter>();
                   string fileWaterMeters = @"E:\Stellar Water Point2\WaterMeters.json";
   
                   FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
   
                   if (fiWaterMeters.Exists == true)
                   {
                       strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                       waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
   
                       IEnumerable<WaterMeter> meters = from   measure
                                                        in     waterMeters
                                                        where  measure.MeterNumber == strMeterNumber
                                                        select measure;
   
                       foreach (WaterMeter meter in waterMeters)
                       {
                           txtMeterDetails.Text = meter.Make + " " +
                                                  meter.Model +
                                                  " (Meter Size: " + meter.MeterSize + ")";
                       }
                   }
               }
           }
   
           private void btnClose_Click(object sender, EventArgs e)
           {
               Close();
           }
       }
   }

8. In the Solution Explorer, below the Customers folder, double-click Central.cs to open its form
9. From the Toolbox, add a button to the form below the list view and to the right of the New Customer Account button
10. Change the characteristics of the button as follows:

    

    Control		(Name)	Other Properties
    ListView		lvwWaterMeters	No Change
    Button		No Change	No Change
    Button		btnCustomerAccountDetails	Customer Account &Details... Anchor: Bottom, Right

11. Double-click the Customer Account &Details button
12. Change the document as follows:

    using System.Data;
    using Microsoft.Data.SqlClient;
    
    namespace StellarWaterPoint31.Customers
    {
        public partial class Central : Form
        {
            public Central()
            {
                InitializeComponent();
            }
    
            private void ShowCustomers()
            {
                . . .
            }
    
            private void Central_Load(object sender, EventArgs e)
            {
                ShowCustomers();
            }
    
            private void btnCreateCustomerAccount_Click(object sender, EventArgs e)
            {
                . . .
            }
    
            private void btnCustomerAccountDetails_Click(object sender, EventArgs e)
            {
                Details details = new();
    
                details.ShowDialog();
    
                ShowCustomers();
            }
        }
    }

13. To execute the application, on the main menu, click Debug -> Start Without Debugging

    

14. On the Water Distribution form, click the Customers button
15. On the Central form of the customers form, click the Customer Account &Details button:

    

16. In the Account # text, type 4086-938-4783
17. Click the Find Customer Account button:

    

18. Close the forms and return to your programming environment

Editing a Customer Account

.

Practical Learning: Editing a Customer Account

1. To create a form, in the Solution Explorer, right-click WaterMeters -> Add -> Form (Windows Forms)...
2. For the Name of the file, type Editor as the name of the form
3. Click Add
4. Design the form as follows:

   

   Control		(Name)	Text	Other Properties
   Label			&Account #:
   MaskedTextBox		mtbAccountNumber		Masked: 0000-000-0000
   Button		btnFindCustomerAccount	&Find Customer Account
   Label			&Account Name:
   TextBox		txtAccountName
   Label			&Meter #:
   MaskedTextBox		mtbMeterNumber		Masked: 000-000-000
   Button		btnFindWaterMeter	Find &Water Meter
   Label			Meter &Details:
   TextBox		txtMeterDetails		Enabled: False
   Label			&Account Type:
   ComboBox		cbxAccountsTypes
   Label			&Address:
   TextBox		txtAddress
   Label			C&ity:
   TextBox		txtCity
   Label			C&ounty:
   TextBox		txtCounty
   Label			&State:
   TextBox		txtState
   Label			&ZIP-Code:
   MaskedTextBox		mtbZIPCode		Masked: Zip-Code
   Button		btnUpdateCustomerAccount	&Update Customer Account	DialogResult: OK
   Button		btnClose	&Close	DialogResult: Cancel

5. Double-click an unoccupied area of the form to generate its Load event
6. Change the document as follows:

   using System.Text.Json;
   using StellarWaterPoint4.Models;
   
   namespace StellarWaterPoint4.Customers
   {
       public partial class Editor : Form
       {
           public Editor()
           {
               InitializeComponent();
           }
   
           private void Editor_Load(object sender, EventArgs e)
           {
               string strAccountsTypes = string.Empty;
               List<AccountType> types = new List<AccountType>();
               string fileAccountsTypes = @"E:\Stellar Water Point2\AccountsTypes.json";
   
               FileInfo fiAccountsTypes = new FileInfo(fileAccountsTypes);
   
               if (fiAccountsTypes.Exists == true)
               {
                   strAccountsTypes = File.ReadAllText(fiAccountsTypes.FullName);
                   types = JsonSerializer.Deserialize<List<AccountType>>(strAccountsTypes)!;
   
                   foreach (AccountType type in types)
                   {
                       cbxAccountsTypes.Items.Add(type.TypeCode + " - " + type.TypeDecription);
                   }
               }
           }
       }
   }

7. Return to the form, double-click the Find Customer Account button
8. Change the document as follows:

   using System.Text.Json;
   using StellarWaterPoint4.Models;
   
   namespace StellarWaterPoint4.Customers
   {
       public partial class Editor : Form
       {
           public Editor()
           {
               InitializeComponent();
           }
   
           private void Editor_Load(object sender, EventArgs e)
           {
               . . .
           }
   
           private void btnFindCustomerAccount_Click(object sender, EventArgs e)
           {
               string strCustomers = string.Empty;
               List<Customer> clients = new List<Customer>();
               string fileCustomers = @"E:\Stellar Water Point2\Customers.json";
   
               FileInfo fiCustomers = new FileInfo(fileCustomers);
   
               if (fiCustomers.Exists == true)
               {
                   using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                   {
                       strCustomers = File.ReadAllText(fiCustomers.FullName);
                       clients = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
   
                       IEnumerable<Customer> customers = from consumer
                                                         in clients
                                                         where consumer.AccountNumber == mtbAccountNumber.Text
                                                         select consumer;
   
                       foreach (Customer client in customers)
                       {
                           txtAccountName.Text = client.AccountName;
                           mtbMeterNumber.Text = client.MeterNumber;
                           cbxAccountsTypes.Text = client.AccountType;
                           txtAddress.Text = client.Address;
                           txtCity.Text = client.City;
                           txtCounty.Text = client.County;
                           txtState.Text = client.State;
                           mtbZIPCode.Text = client.ZIPCode;
                       }
                   }
               }
   
               if( !string.IsNullOrEmpty(mtbMeterNumber.Text) )
               {
                   string strWaterMeters = string.Empty;
                   List<WaterMeter> waterMeters = new List<WaterMeter>();
                   string fileWaterMeters = @"E:\Stellar Water Point2\WaterMeters.json";
   
                   FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
                   
                   if (fiWaterMeters.Exists == true)
                   {
                       strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                       waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
                       
                       foreach (WaterMeter meter in waterMeters)
                       {
                           if (meter.MeterNumber == mtbMeterNumber.Text)
                           {
                               txtMeterDetails.Text = meter.Make + " " +
                                                      meter.Model +
                                                      " (Meter Size: " + meter.MeterSize + ")";
                           }
                       }
                   }
               }
           }
       }
   }

9. Return to the form and double-click the Find Water Meter button
10. Change the document as follows:

    using System.Text.Json;
    using StellarWaterPoint4.Models;
    
    namespace StellarWaterPoint4.Customers
    {
        public partial class Editor : Form
        {
            public Editor()
            {
                InitializeComponent();
            }
    
            private void Editor_Load(object sender, EventArgs e)
            {
                . . .
            }
    
            private void btnFindCustomerAccount_Click(object sender, EventArgs e)
            {
                . . .
            }
    
            private void btnFindWateMeter_Click(object sender, EventArgs e)
            {
                if (string.IsNullOrEmpty(mtbMeterNumber.Text))
                {
                    MessageBox.Show("You must type a valid meter number, " +
                                    "and then click the Find Water Meter button.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                string strWaterMeters = string.Empty;
                List<WaterMeter> waterMeters = new List<WaterMeter>();
                string fileWaterMeters = @"E:\Stellar Water Point2\WaterMeters.json";
    
                FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
    
                if (fiWaterMeters.Exists == true)
                {
                    strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                    waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
    
                    foreach (WaterMeter meter in waterMeters)
                    {
                        if (meter.MeterNumber == mtbMeterNumber.Text)
                        {
                            txtMeterDetails.Text = meter.Make  + " " +
                                                   meter.Model +
                                                   " (Meter Size: " + meter.MeterSize + ")";
                        }
                    }
                }
            }
        }
    }

11. Return to the form and double-click the Update Water Meter button
12. Return to the form and double-click the Close button
13. Change the document as follows:

    using System.Text.Json;
    using StellarWaterPoint4.Models;
    using StellarWaterPoint4.WaterMeters;
    
    namespace StellarWaterPoint4.Customers
    {
        public partial class Editor : Form
        {
            public Editor()
            {
                InitializeComponent();
            }
    
            private void Editor_Load(object sender, EventArgs e)
            {
                string strAccountsTypes = string.Empty;
                List<AccountType> types = new List<AccountType>();
                string fileAccountsTypes = @"E:\Stellar Water Point2\AccountsTypes.json";
    
                FileInfo fiAccountsTypes = new FileInfo(fileAccountsTypes);
    
                if (fiAccountsTypes.Exists == true)
                {
                    strAccountsTypes = File.ReadAllText(fiAccountsTypes.FullName);
                    types = JsonSerializer.Deserialize<List<AccountType>>(strAccountsTypes)!;
    
                    foreach (AccountType type in types)
                    {
                        cbxAccountsTypes.Items.Add(type.TypeCode + " - " + type.TypeDecription);
                    }
                }
            }
    
            private void btnFindCustomerAccount_Click(object sender, EventArgs e)
            {
                if (string.IsNullOrEmpty(mtbAccountNumber.Text))
                {
                    MessageBox.Show("Please an account number of an existing customer. " +
                                    "Then click the Find Customer Account button.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
    
                string strCustomers = string.Empty;
                List<Customer> clients = new List<Customer>();
                string fileCustomers = @"E:\Stellar Water Point2\Customers.json";
    
                FileInfo fiCustomers = new FileInfo(fileCustomers);
    
                if (fiCustomers.Exists == true)
                {
                    using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                    {
                        strCustomers = File.ReadAllText(fiCustomers.FullName);
                        clients = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
    
                        IEnumerable<Customer> customers = from consumer
                                                          in clients
                                                          where consumer.AccountNumber == mtbAccountNumber.Text
                                                          select consumer;
    
                        foreach (Customer client in customers)
                        {
                            txtAccountName.Text = client.AccountName;
                            mtbMeterNumber.Text = client.MeterNumber;
                            cbxAccountsTypes.Text = client.AccountType;
                            txtAddress.Text = client.Address;
                            txtCity.Text = client.City;
                            txtCounty.Text = client.County;
                            txtState.Text = client.State;
                            mtbZIPCode.Text = client.ZIPCode;
                        }
                    }
                }
    
                if (!string.IsNullOrEmpty(mtbMeterNumber.Text))
                {
                    string strWaterMeters = string.Empty;
                    List<WaterMeter> waterMeters = new List<WaterMeter>();
                    string fileWaterMeters = @"E:\Stellar Water Point2\WaterMeters.json";
    
                    FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
    
                    if (fiWaterMeters.Exists == true)
                    {
                        strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                        waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
    
                        foreach (WaterMeter meter in waterMeters)
                        {
                            if (meter.MeterNumber == mtbMeterNumber.Text)
                            {
                                txtMeterDetails.Text = meter.Make + " " +
                                                       meter.Model +
                                                       " (Meter Size: " + meter.MeterSize + ")";
                            }
                        }
                    }
                }
            }
    
            private void btnFindWateMeter_Click(object sender, EventArgs e)
            {
                if (string.IsNullOrEmpty(mtbMeterNumber.Text))
                {
                    MessageBox.Show("You must type a valid meter number, " +
                                    "and then click the Find Water Meter button.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                string strWaterMeters = string.Empty;
                List<WaterMeter> waterMeters = new List<WaterMeter>();
                string fileWaterMeters = @"E:\Stellar Water Point2\WaterMeters.json";
    
                FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
    
                if (fiWaterMeters.Exists == true)
                {
                    strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                    waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
    
                    foreach (WaterMeter meter in waterMeters)
                    {
                        if (meter.MeterNumber == mtbMeterNumber.Text)
                        {
                            txtMeterDetails.Text = meter.Make + " " +
                                                   meter.Model +
                                                   " (Meter Size: " + meter.MeterSize + ")";
                        }
                    }
                }
            }
    
            private void btnUpdateCustomerAccount_Click(object sender, EventArgs e)
            {
                if (string.IsNullOrEmpty(mtbAccountNumber.Text))
                {
                    MessageBox.Show("Please enter an account number for a customer. " +
                                    "You can then click the Find Customer Account button " +
                                    "to indicate the customer whose account you want o update.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                if (string.IsNullOrEmpty(mtbMeterNumber.Text))
                {
                    MessageBox.Show("You must type a valid meter number, " +
                                    "and then click the Find Water Meter button.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                string strCustomers = string.Empty;
                List<Customer> clients = new List<Customer>();
                string fileCustomers = @"E:\Stellar Water Point2\Customers.json";
    
                FileInfo fiCustomers = new FileInfo(fileCustomers);
    
                if (fiCustomers.Exists == true)
                {
                    strCustomers = File.ReadAllText(fiCustomers.FullName);
                    clients = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
    
                    Customer? customer = clients.Find(cust => cust.AccountNumber == mtbAccountNumber.Text);
                                
                    if(customer is not null)
                    {
                        customer.AccountName = txtAccountName.Text;
                        customer.MeterNumber = mtbMeterNumber.Text;
                        customer.AccountType = cbxAccountsTypes.Text;
                        customer.Address = txtAddress.Text;
                        customer.City = txtCity.Text;
                        customer.County = txtCounty.Text;
                        customer.State = txtState.Text;
                        customer.ZIPCode = mtbZIPCode.Text;
    
                        JsonSerializerOptions options = new JsonSerializerOptions();
                        options.WriteIndented = true;
    
                        string jsCustomers = JsonSerializer.Serialize(clients, typeof(List<Customer>), options);
                        File.WriteAllText(fiCustomers.FullName, jsCustomers);
                    };
                }
    
                Close();
            }
    
            private void btnClose_Click(object sender, EventArgs e)
            {
                Close();
            }
        }
    }

14. In the Solution Explorer, below the Customers folder, double-click Central.cs
15. From the Toolbox, add a button to the form below the list view and on the right side of the Customer Account Editor button
16. Change the characteristics of the button as follows:

    

    Control		(Name)	Other Properties
    ListView		lvwCustomers	No Change
    Button		btnNewCustomerAccount	No Change
    Button		btnCustomerAccountDetails	No Change
    Button		btnUpdateCustomerAccount	&Update Customer Account... Anchor: Bottom, Right

17. Display the Central form of the Customers folder
18. Double-click the Update Customer Account button
19. Change the document as follows:

    using System.Data;
    using Microsoft.Data.SqlClient;
    
    namespace StellarWaterPoint31.Customers
    {
        public partial class Central : Form
        {
            public Central()
            {
                InitializeComponent();
            }
    
            private void ShowCustomers()
            {
                . . .
            }
    
            private void Central_Load(object sender, EventArgs e)
            {
                ShowCustomers();
            }
    
            private void btnCreateCustomerAccount_Click(object sender, EventArgs e)
            {
                . . .
            }
    
            private void btnCustomerAccountDetails_Click(object sender, EventArgs e)
            {
                Details details = new();
    
                details.ShowDialog();
    
                ShowCustomers();
            }
    
            private void btnEditCustomerAccount_Click(object sender, EventArgs e)
            {
                Editor editor = new();
    
                editor.ShowDialog();
    
                ShowCustomers();
            }
        }
    }

20. To execute the application, on the main menu, click Debug -> Start Without Debugging

    

21. On the main form of the application, click the Customers button:

    

22. Click the Edit Customer Account button:

    

23. In the Account # text, type 4086-938-4783
24. Click the Find Customer Account button

    

25. Change the values as follows:

    Account Name: Bernotte Doughnuts
    Meter #:      580-742-825 and click Find Water Meter
    Account Type: BUS	- General Business
    Address:      10103 Hexagon Drive
    City:         Winterstown
    County:       York
    State:        PA
    ZIP-Code:     17402-8828

    

26. Click the Update Customer Account button:

    

27. Close the forms and return to your programming environment

Deleting a Customer Account from the Database

.

Practical Learning: Deleting a Customer Account

1. To create a form, in the Solution Explorer, right-click Customers -> Add -> Form(Windows Forms)...
2. In the Name text box, replace the string with Delete as the name of the form
3. Press Enter
4. Design the form as follows:

   

   Control		(Name)	Text	Other Properties
   Label			&Account #:
   MaskedTextBox		mtbAccountNumber		Masked: 0000-000-0000
   Button		btnFindCustomerAccount	&Find Customer Account
   Label			&Account Name:
   TextBox		txtAccountName		Enabled: False
   Label			Meter &Details:
   TextBox		txtMeterDetails		Enabled: False
   Label			&Account Type:
   TextBox		txtAccountsTypes		Enabled: False
   Label			&Address:
   TextBox		txtAddress		Enabled: False
   Label			C&ity:
   TextBox		txtCity		Enabled: False
   Label			C&ounty:
   TextBox		txtCounty		Enabled: False
   Label			&State:
   TextBox		txtState		Enabled: False
   Label			&ZIP-Code:
   TextBox		txtZIPCode		Enabled: False
   Button		btnDeleteCustomerAccount	&Delete Customer Account
   Button		btnClose	&Close

5. On the form, double-click the Find Customer Account button
6. Change the document as tollows:

   using System.Text.Json;
   using StellarWaterPoint4.Models;
   
   namespace StellarWaterPoint4.Customers
   {
       public partial class Delete : Form
       {
           public Delete()
           {
               InitializeComponent();
           }
   
           private void btnFindCustomerAccount_Click(object sender, EventArgs e)
           {
               if (string.IsNullOrEmpty(mtbAccountNumber.Text))
               {
                   MessageBox.Show("You must type a valid account number of a customer, " +
                                   "and then click the Find Customer Account button.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
   
               string strCustomers    = string.Empty;
               List<Customer> clients = new List<Customer>();
               string fileCustomers   = @"E:\Stellar Water Point2\Customers.json";
   
               FileInfo fiCustomers   = new FileInfo(fileCustomers);
   
               string? strMeterNumber = string.Empty;
   
               if (fiCustomers.Exists == true)
               {
                   using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                   {
                       strCustomers  = File.ReadAllText(fiCustomers.FullName);
                       clients       = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
   
                       IEnumerable<Customer> customers = from consumer
                                                         in clients
                                                         where consumer.AccountNumber == mtbAccountNumber.Text
                                                         select consumer;
   
                       foreach (Customer client in customers)
                       {
                           txtAccountName.Text = client.AccountName;
                           strMeterNumber      = client.MeterNumber;
                           txtAccountType.Text = client.AccountType;
                           txtAddress.Text     = client.Address;
                           txtCity.Text        = client.City;
                           txtCounty.Text      = client.County;
                           txtState.Text       = client.State;
                           txtZIPCode.Text     = client.ZIPCode;
                       }
                   }
               }
   
               if (strMeterNumber!.Length > 0)
               {
                   string strWaterMeters = string.Empty;
                   List<WaterMeter> waterMeters = new List<WaterMeter>();
                   string fileWaterMeters = @"E:\Stellar Water Point2\WaterMeters.json";
   
                   FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
   
                   if (fiWaterMeters.Exists == true)
                   {
                       strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                       waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
   
                       IEnumerable<WaterMeter> meters = from measure
                                                        in waterMeters
                                                        where measure.MeterNumber == strMeterNumber
                                                        select measure;
   
                       foreach (WaterMeter meter in waterMeters)
                       {
                           txtMeterDetails.Text = meter.Make + " " +
                                                  meter.Model +
                                                  " (Meter Size: " + meter.MeterSize + ")";
                       }
                   }
               }
           }
       }
   }

7. Return to the form and double-click the Delete Customer Account button
8. Return to the form and double-click the Close button
9. Implement the event as tollows:

   using System.Text.Json;
   using StellarWaterPoint4.Models;
   
   namespace StellarWaterPoint4.Customers
   {
       public partial class Delete : Form
       {
           public Delete()
           {
               InitializeComponent();
           }
   
           private void btnFindCustomerAccount_Click(object sender, EventArgs e)
           {
               if (string.IsNullOrEmpty(mtbAccountNumber.Text))
               {
                   MessageBox.Show("You must type a valid account number of a customer, " +
                                   "and then click the Find Customer Account button.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
   
               string strCustomers    = string.Empty;
               List<Customer> clients = new List<Customer>();
               string fileCustomers   = @"E:\Stellar Water Point2\Customers.json";
   
               FileInfo fiCustomers   = new FileInfo(fileCustomers);
   
               string? strMeterNumber = string.Empty;
   
               if (fiCustomers.Exists == true)
               {
                   using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                   {
                       strCustomers   = File.ReadAllText(fiCustomers.FullName);
                       clients        = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
   
                       IEnumerable<Customer> customers = from consumer
                                                         in clients
                                                         where consumer.AccountNumber == mtbAccountNumber.Text
                                                         select consumer;
   
                       foreach (Customer client in customers)
                       {
                           txtAccountName.Text = client.AccountName;
                           strMeterNumber      = client.MeterNumber;
                           txtAccountType.Text = client.AccountType;
                           txtAddress.Text     = client.Address;
                           txtCity.Text        = client.City;
                           txtCounty.Text      = client.County;
                           txtState.Text       = client.State;
                           txtZIPCode.Text     = client.ZIPCode;
                       }
                   }
               }
   
               if (strMeterNumber!.Length > 0)
               {
                   string strWaterMeters = string.Empty;
                   List<WaterMeter> waterMeters = new List<WaterMeter>();
                   string fileWaterMeters = @"E:\Stellar Water Point2\WaterMeters.json";
   
                   FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
   
                   if (fiWaterMeters.Exists == true)
                   {
                       strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                       waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
   
                       IEnumerable<WaterMeter> meters = from measure
                                                        in waterMeters
                                                        where measure.MeterNumber == strMeterNumber
                                                        select measure;
   
                       foreach (WaterMeter meter in waterMeters)
                       {
                           txtMeterDetails.Text = meter.Make + " " +
                                                  meter.Model +
                                                  " (Meter Size: " + meter.MeterSize + ")";
                       }
                   }
               }
           }
   
           private void btnDeleteCustomerAccount_Click(object sender, EventArgs e)
           {
               if (string.IsNullOrEmpty(mtbAccountNumber.Text))
               {
                   MessageBox.Show("You must type a valid account number of a customer, " +
                                   "and then click the Find Customer Account button. " +
                                   "Only then can you delete an customer account.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
   
               string strCustomers = string.Empty;
               List<Customer> clients = new List<Customer>();
               string fileCustomers = @"E:\Stellar Water Point2\Customers.json";
   
               FileInfo fiCustomers = new FileInfo(fileCustomers);
   
               if (fiCustomers.Exists == true)
               {
                   strCustomers = File.ReadAllText(fiCustomers.FullName);
                   clients = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
   
                   Customer client = clients.Find(acnt => acnt.AccountNumber == mtbAccountNumber.Text)!;
   
                   if (client is not null)
                   {
                       if (MessageBox.Show("Are you sure you want to delete this customer's account " +
                                           "(you cannot undo the action)?",
                                           "Stellar Water Point",
                                           MessageBoxButtons.YesNo,
                                           MessageBoxIcon.Information) == DialogResult.Yes)
                       {
                           clients.Remove(client);
   
                           JsonSerializerOptions options = new JsonSerializerOptions();
                           options.WriteIndented = true;
   
                           string jsCustomers = JsonSerializer.Serialize(clients, typeof(List<Customer>), options);
                           File.WriteAllText(fiCustomers.FullName, jsCustomers);
   
                           MessageBox.Show("The customer's account has been deleted from our system.",
                                           "Stellar Water Point", MessageBoxButtons.OK, MessageBoxIcon.Information);
                       }
                   }
               }
   
               Close();
           }
   
           private void btnClose_Click(object sender, EventArgs e)
           {
               Close();
           }
       }
   }

10. In the Solution Explorer, below the Customers folder, double-click Central.cs
11. From the Toolbox, add two buttons to the form below the list view and on the right side of the Update Customer Account button
12. Change the characteristics of the buttons as follows:

    

    Control		(Name)	Other Properties
    ListView		lvwCustomers	FullRowSelect: True GridLines: True View: Details Anchor: Top, Bottom, Left, Right
    Button		btnCreateCustomerAccount	Create Customer &Account.... Anchor: Bottom, Right
    Button		btnCustomerAccountDetails	Customer Account &Details... Anchor: Bottom, Right
    Button		btnEditCustomerAccount	&Edit Customer Account... Anchor: Bottom, Right
    Button		btnDeleteCustomerAccount	&Delete Customer Account... Anchor: Bottom, Right
    Button		btnClose	&Close Anchor: Bottom, Right

13. On the form, double-click the Delete Customer Account button
14. Return to the Central form of the water meters and double-click the Close button
15. Change the document as follows:

    using StellarWaterPoint4.Models;
    using System.Text.Json;
    
    namespace StellarWaterPoint4.Customers
    {
        public partial class Central : Form
        {
            public Central()
            {
                InitializeComponent();
            }
    
            private void ShowCustomers()
            {
                string strCustomers = string.Empty;
                List<Customer> clients = new List<Customer>();
                string fileCustomers = @"E:\Stellar Water Point2\Customers.json";
    
                FileInfo fiCustomers = new FileInfo(fileCustomers);
    
                if (fiCustomers.Exists == true)
                {
                    using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                    {
                        strCustomers = File.ReadAllText(fiCustomers.FullName);
                        clients = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
    
                        int counter = 1;
    
                        lvwCustomers.Items.Clear();
    
                        foreach (Customer client in clients)
                        {
                            ListViewItem lviCustomer = new ListViewItem(counter++.ToString());
    
                            lviCustomer.SubItems.Add(client.AccountNumber);
                            lviCustomer.SubItems.Add(client.AccountName);
                            lviCustomer.SubItems.Add(client.MeterNumber);
                            lviCustomer.SubItems.Add(client.AccountType);
                            lviCustomer.SubItems.Add(client.Address);
                            lviCustomer.SubItems.Add(client.City);
                            lviCustomer.SubItems.Add(client.County);
                            lviCustomer.SubItems.Add(client.State);
                            lviCustomer.SubItems.Add(client.ZIPCode);
    
                            lvwCustomers.Items.Add(lviCustomer);
                        }
                    }
                }
            }
    
            private void Central_Load(object sender, EventArgs e)
            {
                ShowCustomers();
            }
    
            private void btnCreateCustomerAccount_Click(object sender, EventArgs e)
            {
                Create create = new();
    
                if (create.ShowDialog() == DialogResult.OK)
                {
                    if (string.IsNullOrEmpty(create.mtbAccountNumber.Text))
                    {
                        MessageBox.Show("You must provide an account number for a new customer. " +
                                        "Otherwise, the account cannot be created.",
                                        "Stellar Water Point", MessageBoxButtons.OK);
                        return;
                    }
    
                    if (string.IsNullOrEmpty(create.mtbMeterNumber.Text))
                    {
                        MessageBox.Show("You must type a valid meter number to associate " +
                                        "a water meter to a customer's account. After providing " +
                                        "a meter number, click the Find Water Meter button.",
                                        "Stellar Water Point", MessageBoxButtons.OK);
                        return;
                    }
    
                    string strCustomers = string.Empty;
                    List<Customer> clients = new List<Customer>();
                    string fileCustomers = @"E:\Stellar Water Point2\Customers.json";
    
                    FileInfo fiCustomers = new FileInfo(fileCustomers);
    
                    if (fiCustomers.Exists == true)
                    {
                        strCustomers = File.ReadAllText(fiCustomers.FullName);
                        clients = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
                    }
    
                    Customer client = new Customer()
                    {
                        AccountNumber = create.mtbAccountNumber.Text,
                        AccountName = create.txtAccountName.Text,
                        MeterNumber = create.mtbMeterNumber.Text,
                        AccountType = create.cbxAccountsTypes.Text,
                        Address = create.txtAddress.Text,
                        City = create.txtCity.Text,
                        County = create.txtCounty.Text,
                        State = create.txtState.Text,
                        ZIPCode = create.mtbZIPCode.Text
                    };
    
                    clients.Add(client);
    
                    JsonSerializerOptions options = new JsonSerializerOptions();
                    options.WriteIndented = true;
    
                    string jsCustomers = JsonSerializer.Serialize(clients, typeof(List<Customer>), options);
                    File.WriteAllText(fiCustomers.FullName, jsCustomers);
                }
    
                ShowCustomers();
            }
    
            private void btnCustomerAccountDetails_Click(object sender, EventArgs e)
            {
                Details details = new();
    
                details.Show();
            }
    
            private void btnEditCustomerAccount_Click(object sender, EventArgs e)
            {
                Editor editor = new();
    
                editor.ShowDialog();
    
                ShowCustomers();
            }
    
            private void btnDeleteCustomerAccount_Click(object sender, EventArgs e)
            {
                Delete delete = new();
    
                delete.ShowDialog();
    
                ShowCustomers();
            }
    
            private void btnClose_Click(object sender, EventArgs e)
            {
                Close();
            }
        }
    }

16. To execute the application, on the main menu, click Debug -> Start Without Debugging:

    

17. On the Central form, click the Customers button:

    

18. On the Central form of the customers, click the Delete Customer Account button:

    

19. In the Account # text box, type 7080-583-5947
20. Click the Find Customer Account button:

    

21. Click the Delete Customer Account button
22. Read the text on the message box.
    On the message box, click Yes

    

23. In the same way, delete the other two records
24. Close the forms and return to your programming environment
25. In the Colution Eplorer, below Models, double-click Repository.cs to open its class
26. In the Repository class, add the following method:

    using System.Text.Json;
    
    namespace StellarWaterPoint4.Models
    {
        public static class Repository
        {
            public static void CreateAccountsTypes()
            {
                . . .
            }
    
            public static void CreateWaterMeters()
            {
                . . .
            }
    
            public static void CreateCustomers()
            {
                List<Customer> customers = new List<Customer>();
    
                customers!.Add(new Customer() { AccountNumber = "9279-570-8394", AccountName = "Thomas Stones",                     MeterNumber = "799-528-461", AccountType = "RES - Residential Household", Address = "10252 Broward Ave #D4", City = "Frederick", County = "Frederick", State = "MD", ZIPCode = "21703-4422" });
                customers.Add(new Customer()  { AccountNumber = "4086-938-4783", AccountName = "Bernotte's Doughnuts",              MeterNumber = "580-742-825", AccountType = "BUS - General Business", Address = "10103 Hexagon Drv", City = "Winterstown", County = "York", State = "PA", ZIPCode = "17402-8818" });
                customers.Add(new Customer()  { AccountNumber = "2068-258-9486", AccountName = "Yollanda Training",                 MeterNumber = "186-962-805", AccountType = "UUO - Unidentified or Unclassified Type of Organization", Address = "4819 East Munk Street", City = "Whitehall", County = "Fulton", State = "PA", ZIPCode = "17340-1188" });
                customers.Add(new Customer()  { AccountNumber = "",              AccountName = "First Methodist Congregation",      MeterNumber = "",            AccountType = "",    Address = "7702 Charles Road", City = "", County = "", State = "", ZIPCode = "" });
                customers.Add(new Customer()  { AccountNumber = "6986-829-3741", AccountName = "Eyes Wide",                         MeterNumber = "208-428-308", AccountType = "BUS - General Business", Address = "12087 Avencia Court #4D1", City = "Silver Spring", County = "Montgomery", State = "MD", ZIPCode = "20910-2288" });
                customers.Add(new Customer()  { AccountNumber = "4293-802-8506", AccountName = "Kelly Davids",                      MeterNumber = "496-813-794", AccountType = "RES - Residential Household", Address = "938 East Panchot Str", City = "Greenwood", County = "Sussex", State = "DE", ZIPCode = "19950-4242" });
                customers.Add(new Customer()  { AccountNumber = "9947-374-2648", AccountName = "Marianne Harrington",               MeterNumber = "862-715-006", AccountType = "RES - Residential Household", Address = "708 Correta Drv", City = "Arlington", County = "", State = "VA", ZIPCode = "22222-6060" });
                customers.Add(new Customer()  { AccountNumber = "7928-131-4850", AccountName = "",                                  MeterNumber = "",            AccountType = "SGO - Social/Government/Non-Profit Organization", Address = "", City = "Washington", County = "", State = "", ZIPCode = "" });
                customers.Add(new Customer()  { AccountNumber = "1386-949-2058", AccountName = "Watson Country Buffet",             MeterNumber = "296-837-495", AccountType = "WAT - Water Intensive Business(Laudromat, Hair Salon, Restaurant, etc", Address = "4862 Wellington Street", City = "Hammonton", County = "Atlantic ", State = "NJ", ZIPCode = "08037-2828" });
                customers.Add(new Customer()  { AccountNumber = "7943-686-9786", AccountName = "Angel Bulzaides",                   MeterNumber = "394-835-297", AccountType = "RES - Residential Household", Address = "10227 Old Harbor Drv", City = "Elkview", County = "Kanawha", State = "WV", ZIPCode = "25071-5858" });
                customers.Add(new Customer()  { AccountNumber = "4820-375-2842", AccountName = "Sun Communal",                      MeterNumber = "392-494-572", AccountType = "SGO - Social/Government/Non-Profit Organization", Address = "748 Red Hills Rd", City = "Roanoke", County = "", State = "VA", ZIPCode = "24012-4824" });
                customers.Add(new Customer()  { AccountNumber = "9618-579-2577", AccountName = "Gerald Place",                      MeterNumber = "847-252-246", AccountType = "UUO - Unidentified or Unclassified Type of Organization", Address = "3666 Hanchor Drv", City = "Granville", County = "Licking", State = "OH", ZIPCode = "43023-2777" });
                customers.Add(new Customer()  { AccountNumber = "",              AccountName = "Astral Sequence",                   MeterNumber = "",            AccountType = "BUS - General Business", Address = "12715 Eastern Gateway", City = "Catonsville", County = "Baltimore County", State = "", ZIPCode = "" });
                customers.Add(new Customer()  { AccountNumber = "6003-386-3955", AccountName = "Mandiakandara Marmoudi",            MeterNumber = "374-886-284", AccountType = "OTH - Other", Address = "539 Avalon Court", City = "Greenwood", County = "Sussex", State = "DE", ZIPCode = "19950-5550" });
                customers.Add(new Customer()  { AccountNumber = "5294-859-7513", AccountName = "Jeannette Schiller",                MeterNumber = "713-942-058", AccountType = "RES - Residential Household", Address = "10110 Winslow Ave", City = "Mercerville", County = "Mercer", State = "NJ", ZIPCode = "08619-7472" });
                customers.Add(new Customer()  { AccountNumber = "9249-379-6848", AccountName = "Country West Eatery",               MeterNumber = "588-279-663", AccountType = "BUS - General Business", Address = "8280 Sligo North Way", City = "Albright", County = "Preston", State = "WV", ZIPCode = "26519-6620" });
                customers.Add(new Customer()  { AccountNumber = "5252-757-9595", AccountName = "",                                  MeterNumber = "379-386-979", AccountType = "",    Address = "4992 Preston Street", City = "", County = "", State = "OH", ZIPCode = "" });
                customers.Add(new Customer()  { AccountNumber = "7080-583-5947", AccountName = "Sunny Yard",                        MeterNumber = "827-508-248", AccountType = "WAT - Water Intensive Business(Laudromat, Hair Salon, Restaurant, etc", Address = "663 Sherry Wood East Street", City = "Shimpstown", County = "Franklin", State = "PA", ZIPCode = "17236-2626" });
                customers.Add(new Customer()  { AccountNumber = "8027-304-6829", AccountName = "Anthony Clarcksons",                MeterNumber = "837-806-836", AccountType = "RES - Residential Household", Address = "904 Augusta Drive", City = "Blackbird", County = "New Castle", State = "DE", ZIPCode = "19734-8822" });
                customers.Add(new Customer()  { AccountNumber = "6699-396-2905", AccountName = "Spencer Reuter",                    MeterNumber = "649-373-505", AccountType = "RES - Residential Household", Address = "2850 Burnsweak Avenue", City = "Silver Spring", County = "Montgomery", State = "MD", ZIPCode = "20910-4044" });
                customers.Add(new Customer()  { AccountNumber = "1827-395-0203", AccountName = "Sathyavanthara Khooni",             MeterNumber = "470-628-850", AccountType = "WAT - Water Intensive Business(Laudromat, Hair Salon, Restaurant, etc", Address = "10331 Chryswell Road", City = "Washington", County = "", State = "DC", ZIPCode = "20008-2426" });
                customers.Add(new Customer()  { AccountNumber = "",              AccountName = "Eastern Cage",                      MeterNumber = "",            AccountType = "",    Address = "", City = "Hammonton", County = "", State = "NJ", ZIPCode = "" });
                customers.Add(new Customer()  { AccountNumber = "3947-957-4958", AccountName = "Patsil Industries",                 MeterNumber = "747-581-379", AccountType = "BUS - General Business", Address = "10348 Larrens Drive", City = "Baltimore", County = "Baltimore", State = "MD", ZIPCode = "21215-2222" });
                customers.Add(new Customer()  { AccountNumber = "2836-485-9699", AccountName = "Red Oak High School",               MeterNumber = "379-386-979", AccountType = "SGO - Social/Government/Non-Profit Organization", Address = "442 Donham Road", City = "Silver Spring", County = "Montgomery", State = "MD", ZIPCode = "20910-8822" });
                customers.Add(new Customer()  { AccountNumber = "5938-074-5293", AccountName = "Park and Roll",                     MeterNumber = "592-824-957", AccountType = "SGO - Social/Government/Non-Profit Organization", Address = "582G Dunhill Avenue", City = "Lanham", County = "Prince Georges", State = "MD", ZIPCode = "20706-8284" });
                customers.Add(new Customer()  { AccountNumber = "3028-502-9418", AccountName = "Spencer Kershaw",                   MeterNumber = "186-959-757", AccountType = "RES - Residential Household", Address = "338C Grayson Street", City = "Gatchellville", County = "York", State = "PA", ZIPCode = "17352-6464" });
                customers.Add(new Customer()  { AccountNumber = "",              AccountName = "",                                  MeterNumber = "928-317-924", AccountType = "BUS - General Business", Address = "", City = "", County = "", State = "", ZIPCode = "" });
                customers.Add(new Customer()  { AccountNumber = "2974-972-8139", AccountName = "Paul Arnette",                      MeterNumber = "295-770-695", AccountType = "OTH - Other", Address = "8127 Bledsoe Str", City = "Hyattsville", County = "Prince Georges", State = "MD", ZIPCode = "20783-5858" });
                customers.Add(new Customer()  { AccountNumber = "2758-493-7249", AccountName = "Hervey Smile",                      MeterNumber = "293-924-869", AccountType = "WAT - Water Intensive Business(Laudromat, Hair Salon, Restaurant, etc", Address = "12973 Sonaa Street #E42", City = "Silver Spring", County = "Montgomery", State = "MD", ZIPCode = "20910-4488" });
                customers.Add(new Customer()  { AccountNumber = "9337-947-3664", AccountName = "",                                  MeterNumber = "649-358-184", AccountType = "SGO - Social/Government/Non-Profit Organization", Address = "", City = "Bellefontaine", County = "", State = "OH", ZIPCode = "" });
                customers.Add(new Customer()  { AccountNumber = "7518-302-6895", AccountName = "Grace Brenner",                     MeterNumber = "207-964-835", AccountType = "BUS - General Business", Address = "4299 Peachtree Court", City = "Rockville", County = "Montgomery", State = "MD", ZIPCode = "20853-1888" });
                customers.Add(new Customer()  { AccountNumber = "",              AccountName = "Jeffrey Maney",                     MeterNumber = "",            AccountType = "RES - Residential Household", Address = "", City = "", County = "", State = "", ZIPCode = "" });
                customers.Add(new Customer()  { AccountNumber = "7028-405-9381", AccountName = "Valley Services",                   MeterNumber = "306-842-497", AccountType = "WAT - Water Intensive Business(Laudromat, Hair Salon, Restaurant, etc", Address = "613 Meadowhill Road", City = "Alonzaville", County = "Shenandoah", State = "VA", ZIPCode = "22664-8080" });
                customers.Add(new Customer()  { AccountNumber = "5293-957-3395", AccountName = "Wellway Community Center",          MeterNumber = "386-468-057", AccountType = "RES - Residential Household", Address = "10484 Greenway Avenue", City = "Mt Storm", County = "Grant", State = "WV", ZIPCode = "26739-7700" });
                customers.Add(new Customer()  { AccountNumber = "2038-413-9680", AccountName = "Eastern Friandise",                 MeterNumber = "938-725-869", AccountType = "BUS - General Business", Address = "2075 Rose Hills Avenue", City = "Washington", County = "", State = "DC", ZIPCode = "20004-2626" });
                customers.Add(new Customer()  { AccountNumber = "",              AccountName = "Amidou Gomah",                      MeterNumber = "",            AccountType = "RES - Residential Household", Address = "14118 Yellow Burrough Blvd", City = "Philadelphia", County = "", State = "PA", ZIPCode = "" });
                customers.Add(new Customer()  { AccountNumber = "3792-853-6885", AccountName = "Department of Public Affairs",      MeterNumber = "595-753-147", AccountType = "",    Address = "", City = "Upper Marlboro", County = "Prince George County", State = "", ZIPCode = "" });
                customers.Add(new Customer()  { AccountNumber = "8282-777-8282", AccountName = "Garland Hotel",                     MeterNumber = "938-275-294", AccountType = "BUS - General Business", Address = "4222 Extell Ave", City = "Cambridge", County = "", State = "MD", ZIPCode = "21613-2288" });
                customers.Add(new Customer()  { AccountNumber = "",              AccountName = "Single Connection",                 MeterNumber = "288-427-585", AccountType = "BUS - General Business", Address = "", City = "Mansfield", County = "", State = "OH", ZIPCode = "44903-3030" });
                customers.Add(new Customer()  { AccountNumber = "2499-636-4444", AccountName = "Bryanna Spencer",                   MeterNumber = "",            AccountType = "RES - Residential Household", Address = "6282 Sheppherd Str", City = "", County = "Anne Arundel", State = "", ZIPCode = "" });
                customers.Add(new Customer()  { AccountNumber = "2842-585-7260", AccountName = "District Community Reserves",       MeterNumber = "349-725-848", AccountType = "SGO - Social/Government/Non-Profit Organization", Address = "3280 Hopewell Street, NE", City = "Washington", County = "", State = "", ZIPCode = "" });
                customers.Add(new Customer()  { AccountNumber = "9282-794-7937", AccountName = "Yashua Yáñés",                      MeterNumber = "392-494-572", AccountType = "RES - Residential Household", Address = "10214 Monroe Ave", City = "Easton", County = "", State = "MD", ZIPCode = "" });
                customers.Add(new Customer()  { AccountNumber = "",              AccountName = "Miguel Altieri",                    MeterNumber = "",            AccountType = "RES - Residential Household", Address = "10941 Patriot Blvd", City = "Crenshaw", County = "Jefferson", State = "PA", ZIPCode = "15824-6628" });
                customers.Add(new Customer()  { AccountNumber = "2847-597-2829", AccountName = "Jameson",                           MeterNumber = "379-386-979", AccountType = "WAT - Water Intensive Business(Laudromat, Hair Salon, Restaurant, etc", Address = "7373 Gold Town Rd", City = "", County = "", State = "WV", ZIPCode = "" });
                customers.Add(new Customer()  { AccountNumber = "6381-748-2222", AccountName = "Up Eyes",                           MeterNumber = "",            AccountType = "BUS - General Business", Address = "4149 Deerfield Str", City = "", County = "", State = "", ZIPCode = "" });
                customers.Add(new Customer()  { AccountNumber = "",              AccountName = "Annette Wald",                      MeterNumber = "",            AccountType = "RES - Residential Household", Address = "11441  Eastern Friendshi Rd", City = "", County = "", State = "", ZIPCode = "" });
                customers.Add(new Customer()  { AccountNumber = "8384-708-2941", AccountName = "Department of Environment Affairs", MeterNumber = "",            AccountType = "SGO - Social/Government/Non-Profit Organization", Address = "", City = "", County = "", State = "OH", ZIPCode = "" });
                customers.Add(new Customer()  { AccountNumber = "3728-138-2947", AccountName = "Marie Rath",                        MeterNumber = "",            AccountType = "",    Address = "8802 Atlantic Ave", City = "", County = "", State = "PA", ZIPCode = "" });
                customers.Add(new Customer()  { AccountNumber = "1793-857-9413", AccountName = "Body Care",                         MeterNumber = "",            AccountType = "WAT - Water Intensive Business(Laudromat, Hair Salon, Restaurant, etc", Address = "", City = "Ocean City", County = "", State = "NJ", ZIPCode = "" });
                customers.Add(new Customer()  { AccountNumber = "6028-695-2068", AccountName = "Ronald Glassman",                   MeterNumber = "468-359-486", AccountType = "BUS - General Business", Address = "", City = "", County = "", State = "", ZIPCode = "" });
                customers.Add(new Customer()  { AccountNumber = "",              AccountName = "",                                  MeterNumber = "",            AccountType = "WAT - Water Intensive Business(Laudromat, Hair Salon, Restaurant, etc", Address = "8812 Lawrence Ave", City = "", County = "", State = "NW", ZIPCode = "" });
                customers.Add(new Customer()  { AccountNumber = "9616-283-7249", AccountName = "",                                  MeterNumber = "",            AccountType = "SGO - Social/Government/Non-Profit Organization", Address = "13006 Blueberry Ave", City = "", County = "", State = "MD", ZIPCode = "" });
                customers.Add(new Customer()  { AccountNumber = "2829-516-8353", AccountName = "Richard Eghert",                    MeterNumber = "",            AccountType = "RES - Residential Household", Address = "662 Placido Road", City = "", County = "", State = "", ZIPCode = "" });
    
                string strCustomers = string.Empty;
                string fileCustomers = @"E:\Stellar Water Point2\Customers.json";
    
                JsonSerializerOptions options = new JsonSerializerOptions();
                options.WriteIndented = true;
    
                FileInfo fiCustomers = new FileInfo(fileCustomers);
                string jsCustomers = JsonSerializer.Serialize(customers, typeof(List<Customer>), options);
                File.WriteAllText(fiCustomers.FullName, jsCustomers);
            }
        }
    }

27. In the Solution Explorer, double-click WaterDistribution.cs
28. Double-click an unoccupied area of the form
29. Class the function as follows:

    using StellarWaterPoint4.Models;
    
    namespace StellarWaterPoint4
    {
        public partial class WaterDistribution : Form
        {
            public WaterDistribution()
            {
                InitializeComponent();
            }
    
            private void WaterDistribution_Load(object sender, EventArgs e)
            {
                Directory.CreateDirectory(@"E:\Stellar Water Point2");
    
                // Repository.CreateAccountsTypes();
                // Repository.CreateWaterMeters();
                Repository.CreateCustomers();
            }
    
            private void btnCustomers_Click(object sender, EventArgs e)
            {
                Customers.Central central = new();
    
                central.Show();
            }
    
            private void btnWaterMeters_Click(object sender, EventArgs e)
            {
                WaterMeters.Central central = new();
    
                central.Show();
            }
        }
    }

Water Bills

Introduction

.

Practical Learning: Introducing Water Bills

1. To create a folder, in the Solution Explorer, right-click the StellarWaterPoint3 project -> Add -> New Folder
2. Type WaterBills as the name of the folder
3. To create a class, in the Solution Explorer, right-click Models -> Add -> Class...
4. Type WaterBill as the Name of the file
5. Click Add
6. Define the class as follows:

   namespace StellarWaterPoint4.Models
   {
       public class WaterBill
       {
   		public int      BillNumber            { get; set; }
           public string?  AccountNumber         { get; set; }
           public DateTime MeterReadingStartDate { get; set; }
           public DateTime MeterReadingEndDate   { get; set; }
           public int      BillingDays           { get; set; }
           public int      CounterReadingStart   { get; set; }
           public int      CounterReadingEnd     { get; set; }
           public int      TotalHCF              { get; set; }
           public int      TotalGallons          { get; set; }
           public double   FirstTierConsumption  { get; set; }
           public double   SecondTierConsumption { get; set; }
           public double   LastTierConsumption   { get; set; }
           public double   WaterCharges          { get; set; }
           public double   SewerCharges          { get; set; }
           public double   EnvironmentCharges    { get; set; }
           public double   ServiceCharges        { get; set; }
           public double   TotalCharges          { get; set; }
           public double   LocalTaxes            { get; set; }
           public double   StateTaxes            { get; set; }
           public DateTime PaymentDueDate        { get; set; }
           public double   AmountDue             { get; set; }
           public DateTime LatePaymentDueDate    { get; set; }
           public DateTime LateAmountDue         { get; set; }
       }
   }

7. To create another class, in the Solution Explorer, right-click Models -> Add -> Class...
8. Type WaterBillManager as the Name of the file
9. Click Add
10. Define the class as follows:

    namespace StellarWaterPoint31.Models
    {
        internal class WaterBillManager
        {
            internal (double a, double b, double c) CalculateTiers(string acnt, double total)
            {
                (double tier1, double tier2, double tier3) results = (0.00, 0.00, 0.00);
    
                if (acnt == "RES - Residential Household")
                {
                    results.tier1 = total * 41.50 / 10000.00;
                    results.tier2 = total * 32.50 / 10000.00;
                    results.tier3 = total * 26.00 / 10000.00;
                }
                else if (acnt == "SGO - Social/Government/Non-Profit Organization")
                {
                    results.tier1 = total * 46.00 / 10000.00;
                    results.tier2 = total * 50.00 / 10000.00;
                    results.tier3 = total * 4.00  / 10000.00;
                }
                else if (acnt == "BUS - General Business")
                {
                    results.tier1 = total * 45.00 / 10000.00;
                    results.tier2 = total * 30.00 / 10000.00;
                    results.tier3 = total * 25.00 / 10000.00;
                }
                else if (acnt == "UUO - Unidentified or Unclassified Type of Organization")
                {
                    results.tier1 = total * 25.00 / 10000.00;
                    results.tier2 = total * 35.00 / 10000.00;
                    results.tier3 = total * 40.00 / 10000.00;
                }
                else if (acnt == "WAT - Water Intensive Business(Laudromat, Hair Salon, Restaurant, etc")
                {
                    results.tier1 = total * 50.00 / 10000.00;
                    results.tier2 = total * 40.00 / 10000.00;
                    results.tier3 = total * 10.00 / 10000.00;
                }
                else
                {
                    results.tier1 = total * (48.00 / 10000.00);
                    results.tier2 = total * (32.00 / 10000.00);
                    results.tier3 = total * (20.00 / 10000.00);
                }
    
                return results;
            }
    
            internal double CalculateSewerCharges(string acnt, double total)
            {
                double result;
    
                if (acnt == "RES - Residential Household")
                {
                    result = total * 6.826941 / 100.00;
                }
                else if (acnt == "SGO - Social/Government/Non-Profit Organization")
                {
                    result = total * 4.162522 / 100.00;
                }
                else if (acnt == "BUS - General Business")
                {
                    result = total * 8.315136 / 100.00;
                }
                else if (acnt == "UUO - Unidentified or Unclassified Type of Organization")
                {
                    result = total * 10.626147 / 100.00;
                }
                else if (acnt == "WAT - Water Intensive Business(Laudromat, Hair Salon, Restaurant, etc")
                {
                    result = total * 12.025135 / 100.00;
                }
                else // if (acnt == "OTH - Other")
                {
                    result = total * 9.202615 / 100.00;
                }
    
                return result;
            }
    
            internal double CalculateEnvironmentCharges(string acnt, double total)
            {
                double result;
    
                switch (acnt)
                {
                    case "RES - Residential Household":
                        result = total * 0.022724;
                        break;
                    case "SGO - Social/Government/Non-Profit Organization":
                        result = total * 0.118242;
                        break;
                    case "BUS - General Business":
                        result = total * 0.161369;
                        break;
                    case "UUO - Unidentified or Unclassified Type of Organization":
                        result = total * 0.082477;
                        break;
                    case "WAT - Water Intensive Business(Laudromat, Hair Salon, Restaurant, etc":
                        result = total * 0.413574;
                        break;
                    default:
                        result = total * 0.221842;
                        break;
                }
    
                return result;
            }
    
            internal double CalculateServiceCharges(string acnt, double total)
            {
                switch (acnt)
                {
                    case "RES - Residential Household":
                        return total * 0.145748;
                    case "SGO - Social/Government/Non-Profit Organization":
                        return total * 0.102246;
                    case "BUS - General Business":
                        return total * 0.242627;
                    case "UUO - Unidentified or Unclassified Type of Organization":
                        return total * 0.186692;
                    case "WAT - Water Intensive Business(Laudromat, Hair Salon, Restaurant, etc":
                        return total * 0.412628;
                    default:
                        return total * 0.210248;
                }
            }
    
            internal double CalculateLocalTaxes(string acnt, double total) => acnt switch
            {
                "RES - Residential Household" => total * 0.031574,
                "SGO - Social/Government/Non-Profit Organization" => total * 0.035026,
                "BUS - General Business" => total * 0.122517,
                "UUO - Unidentified or Unclassified Type of Organization" => total * 0.105737,
                "WAT - Water Intensive Business(Laudromat, Hair Salon, Restaurant, etc" => total * 0.153248,
                _     => total * 0.125148
            };
    
            internal double CalculateStateTaxes(string acnt, double total) => acnt switch
            {
                "RES - Residential Household" => total * 0.017242,
                "SGO - Social/Government/Non-Profit Organization" => total * 0.008779,
                "BUS - General Business" => total * 0.042448,
                "UUO - Unidentified or Unclassified Type of Organization" => total * 0.067958,
                "WAT - Water Intensive Business(Laudromat, Hair Salon, Restaurant, etc" => total * 0.081622,
                _     => total * 0.013746
            };
    
            internal DateTime SetPaymentDueDate(string acnt, DateTime date)
            {
                TimeSpan tsPaymentDueDate = new TimeSpan(1, 0, 0, 0);
    
                if (acnt == "RES - Residential Household")
                {
                    tsPaymentDueDate = new TimeSpan(15, 0, 0, 0);
                }
                else if (acnt == "SGO - Social/Government/Non-Profit Organization")
                {
                    tsPaymentDueDate = new TimeSpan(20, 0, 0, 0);
                }
                else if (acnt == "BUS - General Business")
                {
                    tsPaymentDueDate = new TimeSpan(30, 0, 0, 0);
                }
                else if (acnt == "UUO - Unidentified or Unclassified Type of Organization")
                {
                    tsPaymentDueDate = new TimeSpan(25, 0, 0, 0);
                }
                else if (acnt == "WAT - Water Intensive Business(Laudromat, Hair Salon, Restaurant, etc")
                {
                    tsPaymentDueDate = new TimeSpan(40, 0, 0, 0);
                }
                else
                {
                    tsPaymentDueDate = new TimeSpan(35, 0, 0, 0);
                }
    
                return date + tsPaymentDueDate;
            }
    
            internal DateTime SetLatePaymentDueDate(string acnt, DateTime date)
            {
                switch (acnt)
                {
                    case "RES - Residential Household":
                        return date + new TimeSpan(30, 0, 0, 0);
                    case "SGO - Social/Government/Non-Profit Organization":
                        return date + new TimeSpan(40, 0, 0, 0);
                    case "BUS - General Business":
                        return date + new TimeSpan(50, 0, 0, 0);
                    case "UUO - Unidentified or Unclassified Type of Organization":
                        return date + new TimeSpan(60, 0, 0, 0);
                    case "WAT - Water Intensive Business(Laudromat, Hair Salon, Restaurant, etc":
                        return date + new TimeSpan(65, 0, 0, 0);
                    default:
                        return date + new TimeSpan(45, 0, 0, 0);
                }
            }
    
            internal double CalculateLateAmountDue(string acnt, double amt) => acnt switch
            {
                "RES - Residential Household" => amt + 8.95,
                "SGO - Social/Government/Non-Profit Organization" => amt + (amt /  4.575),
                "BUS - General Business" => amt + (amt / 12.315),
                "UUO - Unidentified or Unclassified Type of Organization" => amt + (amt /  7.425),
                "WAT - Water Intensive Business(Laudromat, Hair Salon, Restaurant, etc" => amt + (amt / 15.225),
                _     => amt + (amt / 6.735)
            };
        }
    }

Showing Water Bills

.

Practical Learning: Showing Water Bills

1. To create a form, in the Solution Explorer, right-click WaterBills -> Add -> Form (Windows Forms)...
2. For the Name of the form, type Central
3. Click Add
4. In the Toolbox, click the ListView button and click the form
5. On the form, right-click the list view and click Edit Columns...
6. Create the columns as follows:

   (Name)	Text	TextAlign	Width
   colWaterBillId	Id		40
   colBillNumber	Bill #	Center	80
   colAccountSummary	Account Summary	Center	550
   colStartDate	Start Date	Center	150
   colEndDate	End Date	Center	150
   colBillingDays	Days	Center
   colCounterStart	Counter Start	Right	125
   colCounterEnd	Counter End	Right	125
   colTotalHCF	Total HCF	Right	100
   colGallons	Gallons	Right	95
   colPaymentDueDate	Pmt Due Date	Center	125
   colAmountDue	Amt Due	Right	90

7. Click OK
8. Position and resize the list view on the form as follows:

   

   Control		(Name)	Other Properties
   ListView		lvwWaterBills	FullRowSelect: True GridLines: True View: Details Anchor: Top, Bottom, Left, Right

9. Double-click an unoccupied area of the form to generate its Load event
10. Change the document as follows:

    using System.Text.Json;
    using StellarWaterPoint4.Models;
    
    namespace StellarWaterPoint4.WaterBills
    {
        public partial class Central : Form
        {
            public Central()
            {
                InitializeComponent();
            }
    
            private void ShowWaterBills()
            {
                // We will need the list of customers to display an account summary in the list view
                // Declare a strCustomers variable that will hold the records from the JSON file
                string strCustomers     = string.Empty;
                // Prepare a list to hold the records of customers
                List<Customer> clients  = new List<Customer>();
                // Specify the file that holds the records of customers
                string fileCustomers    = @"E:\Stellar Water Point2\Customers.json";
    
                // Create a FileInfo object for the records of customers
                FileInfo fiCustomers    = new FileInfo(fileCustomers);
    
                // Check if a file that holds the records of customers was created already
                if (fiCustomers.Exists  == true)
                {
                    // If that file exists, create a TextReader object to get those records
                    using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                    {
                        // Read the records and store them in the strCustomers variable
                        strCustomers = File.ReadAllText(fiCustomers.FullName);
                        // Use JSON deserialization to get the records of customers
                        clients         = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
                    }
                }
    
                // Declare a strWaterBills variable that will hold the records from the JSON file
                string strWaterBills    = string.Empty;
                // Prepare a bills list to hold the records of water bills
                List<WaterBill> bills   = new List<WaterBill>();
                // Specify the file that holds the records of water bills
                string fileWaterBills   = @"E:\Stellar Water Point2\WaterBills.json";
    
                // Create a FileInfo object for the records of water bills
                FileInfo fiWaterBills   = new FileInfo(fileWaterBills);
    
                // Find out whether a file that holds the records of water bills exists already
                if (fiWaterBills.Exists == true)
                {
                    // If that file exists, create a TextReader object to read the file
                    using (TextReader trWaterBills = new StreamReader(fiWaterBills.FullName))
                    {
                        /* Read the contents of the file that holds the water bills.
                         * Store the read text in the strWaterBills variable that was declared. */
                        strWaterBills = File.ReadAllText(fiWaterBills.FullName);
                        // Get the water bills and store them in the bills list variable
                        bills = JsonSerializer.Deserialize<List<WaterBill>>(strWaterBills)!;
    
                        // This variable will be used to keep count of the water bills records
                        int counter = 1;
    
                        /* We are about to display the water bills records in the list view.
                         * Before proceeding, first remove any record in the list view. */
                        lvwWaterBills.Items.Clear();
    
                        // Visit each record of the water bills
                        foreach (WaterBill client in bills)
                        {
                            /* Prepare a ListViewItem object for each record.
                             * Display the record counter in the first column of this object. */
                            ListViewItem lviWaterBill = new ListViewItem(counter++.ToString());
    
                            // Display the water bill number of the current record
                            lviWaterBill.SubItems.Add(client.BillNumber.ToString());
    
                            /* Refer to the list of records of the customers (that list was prepared earlier).
                             * Use LINQ to get the customer whose account number is 
                             * the same as the account number of the current record. */
                            IEnumerable<Customer> customer = clients.Where(cust => cust.AccountNumber == client.AccountNumber);
    
                            // Now that we have located the customer record, display some details about it
                            foreach (Customer cust in customer)
                            {
                                lviWaterBill.SubItems.Add(client.AccountNumber + " - " + 
                                                          cust.AccountName + 
                                                          ", Type: " + cust.AccountType![..3] + 
                                                          ", (Mtr #: " + cust.MeterNumber + ")");
                            }
    
                            /* Continue displaying some other parts of the water bill.
                             * Before there is not enough space for the whole water bill, we display only some values. */
                            lviWaterBill.SubItems.Add(client.MeterReadingStartDate.ToShortDateString());
                            lviWaterBill.SubItems.Add(client.MeterReadingEndDate.ToShortDateString());
                            lviWaterBill.SubItems.Add(client.BillingDays.ToString());
                            lviWaterBill.SubItems.Add(client.CounterReadingStart.ToString());
                            lviWaterBill.SubItems.Add(client.CounterReadingEnd.ToString());
                            lviWaterBill.SubItems.Add(client.TotalHCF.ToString());
                            lviWaterBill.SubItems.Add(client.TotalGallons.ToString());
                            lviWaterBill.SubItems.Add(client.PaymentDueDate.ToShortDateString());
                            lviWaterBill.SubItems.Add(client.AmountDue.ToString());
    
                            lvwWaterBills.Items.Add(lviWaterBill);
                        }
                    }
                }
            }
    
            private void Central_Load(object sender, EventArgs e)
            {
                ShowWaterBills();
            }
        }
    }

11. In the Solution Explorer, double-click WaterDistribution.cs to display the main form of the application
12. From the Toolbox, add two buttons to the form
13. From the Properties window, change the characteristics of the button as follows:

    

    Control		(Name)	Text	Font
    Button		btnWaterBills	C&Water Bills...	Times New Roman, 24pt, style=Bold
    Button		btnClose	&Close	Times New Roman, 24pt, style=Bold

14. Double-click the &Water Bills button
15. Return to the form and double-click the Close button
16. Impliment the events as follows:

    namespace StellarWaterPoint31
    {
        public partial class WaterDistribution : Form
        {
            public WaterDistribution()
            {
                InitializeComponent();
            }
    
            private void btnWaterBills_Click(object o, EventArgs e)
            {
                WaterBills.Central central = new();
    
                central.Show();
            }
    
            private void btnCustomers_Click(object o, EventArgs e)
            {
                Customers.Central clients = new();
    
                clients.ShowDialog();
            }
    
            private void btnWaterMeters_Click(object o, EventArgs e)
            {
                WaterMeters.Central central = new WaterMeters.Central();
    
                central.ShowDialog();
            }
    
            private void btnClose_Click(object sender, EventArgs e)
            {
                Close();
            }
        }
    }

A New Water Bill

.

Practical Learning: Processing a Water Bill

1. To create a form, in the Solution Explorer, right-click WaterBills -> Add -> Form (Windows Forms)...
2. Set the name to Create
3. Click Add
4. Design the form as follows:

   

   Control		Text	Name	Other Properties
   Label		&Water Bill #:
   TextBox			txtBillNumber
   GroupBox		Customer Information
   Label		&Account #:
   MaskedTextBox			mtbAccountNumber	Mask: 0000-000-0000
   Button		Find Customer &Account	btnFindCustomerAccount
   Label		Account Name:
   TextBox			txtAccountName
   Label		Account Type:
   TextBox			txtAccountType
   Label		Address:
   TextBox			txtAddress
   TextBox			txtCity
   TextBox			txtCounty
   TextBox			txtState
   TextBox			txtZIPCode
   Label		_________________________________________________
   Label		Meter Details:
   TextBox			txtMeterDetails
   GroupBox		Meter Reading
   Label		Meter &Reading Start Date:
   Date Time Picker			dtpMeterReadingStartDate
   Label		Meter Reading &End Date:
   Date Time Picker			dtpMeterReadingEndDate
   Label		Coun&ter Reading Start:
   TextBox			txtCounterReadingStart
   Label		Counter Readi&ng End:
   TextBox			txtCounterReadingEnd
   Button		&Evaluate Water Bill	btnEvaluateWaterBill	Times New Roman, 24pt, style=Bold
   GroupBox		Meter Result
   Label		Billing Days:
   TextBox			txtBillingDays
   Label		Total HCF:
   TextBox			txtTotalHCF
   Label		Total Gallons:
   TextBox			txtTotalGallons
   Label		First Tier Consumption:
   TextBox			txtFirstTierConsumption
   Label		Second Tier:
   TextBox			txtSecondTierConsumption
   Label		Last Tier:
   TextBox			txtLastTierConsumption
   GroupBox		Consumption Charges
   Label		Water Charges:
   TextBox			txtWaterCharges
   Label		Sewer Charges:
   TextBox			txtSewerCharges
   Label		Environment Charges:
   TextBox			txtEnvironmentCharges
   Label		Service Charges:
   TextBox			txtServiceCharges
   Label		Total Charges:
   TextBox			txtTotalCharges
   GroupBox		Taxes
   Label		Local Taxes:
   TextBox			txtLocalTaxes
   Label		State Taxes:
   TextBox			txtStateTaxes
   GroupBox		Water Bill Payment
   Label		Payment Due Date:
   Date Time Picker			dtpPaymentDueDate
   Label		Amount Due:
   TextBox			txtAmountDue
   Label		Late Payment Due Date:
   Date Time Picker			dtpLatePaymentDueDate
   Label		&Late Amount Due:
   TextBox			txtLateAmountDue
   Button		Save Water Bill	btnSaveWaterBill
   Button		&Close	btnClose

   Form Properties

   Form Property	Value
   FormBorderStyle	FixedDialog
   Text	Stellar Water Point - Water Bill Processing
   StartPosition	CenterScreen
   MaximizeBox	False
   MinimizeBox	False

5. On the form, double-click the Find Customer Account button
6. Change the document as follows:

   using System.Text.Json;
   using StellarWaterPoint4.Models;
   
   namespace StellarWaterPoint4.WaterBills
   {
       public partial class Create : Form
       {
           public Create()
           {
               InitializeComponent();
           }
   
           private void btnFindCustomerAccount_Click(object sender, EventArgs e)
           {
               if (string.IsNullOrEmpty(mtbAccountNumber.Text))
               {
                   MessageBox.Show("You must type a valid account number of a customer, " +
                                   "and then click the Find Customer Account button.",
                                   "Stellar Water Point", MessageBoxButtons.OK);
                   return;
               }
   
               string strCustomers    = string.Empty;
               List<Customer> clients = new List<Customer>();
               string fileCustomers   = @"E:\Stellar Water Point2\Customers.json";
   
               FileInfo fiCustomers   = new FileInfo(fileCustomers);
   
               string? strMeterNumber = string.Empty;
   
               if (fiCustomers.Exists == true)
               {
                   using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                   {
                       strCustomers = File.ReadAllText(fiCustomers.FullName);
                       clients = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
   
                       IEnumerable<Customer> customers = clients.Where(cust => cust.AccountNumber == mtbAccountNumber.Text);
   
                       foreach (Customer client in customers)
                       {
                           txtAccountName.Text = client.AccountName;
                           strMeterNumber      = client.MeterNumber;
                           txtAccountType.Text = client.AccountType;
                           txtAddress.Text     = client.Address;
                           txtCity.Text        = client.City;
                           txtCounty.Text      = client.County;
                           txtState.Text       = client.State;
                           txtZIPCode.Text     = client.ZIPCode;
                       }
                   }
               }
   
               if (strMeterNumber!.Length > 0)
               {
                   string strWaterMeters        = string.Empty;
                   List<WaterMeter> waterMeters = new List<WaterMeter>();
                   string fileWaterMeters       = @"E:\Stellar Water Point2\WaterMeters.json";
   
                   FileInfo fiWaterMeters       = new FileInfo(fileWaterMeters);
   
                   if (fiWaterMeters.Exists     == true)
                   {
                       strWaterMeters           = File.ReadAllText(fiWaterMeters.FullName);
                       waterMeters              = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
   
                       IEnumerable<WaterMeter> meters = waterMeters.Where(wm => wm.MeterNumber == strMeterNumber);
   
                       foreach (WaterMeter meter in meters)
                       {
                           txtMeterDetails.Text = meter.Make + " " +
                                                  meter.Model +
                                                  " (Meter Size: " + meter.MeterSize + ")";
                       }
                   }
               }
           }
       }
   }

7. Return to the form and double-click the Meter Reading End Date date time picker to generate its Value Changed event
8. Implement the event as follows:

   using System.Data;
   using Microsoft.Data.SqlClient;
   
   namespace StellarWaterPoint31.WaterBills
   {
       public partial class Create : Form
       {
           public Create()
           {
               InitializeComponent();
           }
   
           private void btnFindCustomerAccount_Click(object sender, EventArgs e)
           {
               . . .
           }
   
           private void dtpMeterReadingEndDate_ValueChanged(object sender, EventArgs e)
           {
               TimeSpan tsDays = dtpMeterReadingEndDate.Value - dtpMeterReadingStartDate.Value;
   
               txtBillingDays.Text = (tsDays.Days + 1).ToString();
           }
       }
   }

9. Return to the form and double-click the Evaluate Water Bill button
10. Implement the event as follows:

    using System.Text.Json;
    using StellarWaterPoint4.Models;
    
    namespace StellarWaterPoint4.WaterBills
    {
        public partial class Create : Form
        {
            public Create()
            {
                InitializeComponent();
            }
    
            private void btnFindCustomerAccount_Click(object sender, EventArgs e)
            {
                . . .
            }
    
            private void dtpMeterReadingEndDate_ValueChanged(object sender, EventArgs e)
            {
                TimeSpan tsDays = dtpMeterReadingEndDate.Value - dtpMeterReadingStartDate.Value;
    
                txtBillingDays.Text = (tsDays.Days + 1).ToString();
            }
    
            private void btnEvaluateWaterBill_Click(object sender, EventArgs e)
            {
                double counterStart = 0, counterEnd = 0;
    
                try
                {
                    counterStart = double.Parse(txtCounterReadingStart.Text);
                }
                catch (FormatException feCRStart)
                {
                    MessageBox.Show("You must enter a valid value in the Counter Reading Start text box. " +
                                    "The error produced is: " + feCRStart.Message,
                                    "Stellar Water Point", MessageBoxButtons.OK, MessageBoxIcon.Information);
                }
    
                try
                {
                    counterEnd = double.Parse(txtCounterReadingEnd.Text);
                }
                catch (FormatException feCREnd)
                {
                    MessageBox.Show("You must enter a valid value in the Counter Reading End text box. " +
                                    "The error produced is: " + feCREnd.Message,
                                    "Stellar Water Point", MessageBoxButtons.OK, MessageBoxIcon.Information);
                }
    
                double consumption            = counterEnd - counterStart;
                double gallons                = consumption * 748.05;
                string strAccountType         = txtAccountType.Text[..3];
    
                (double first, double second, double last) tiers = WaterBillManager.CalculateTiers(strAccountType, gallons);
    
                double waterCharges           = tiers.first + tiers.second + tiers.last;
                double sewerCharges           = WaterBillManager.CalculateSewerCharges(strAccountType, waterCharges);
                double envCharges             = WaterBillManager.CalculateEnvironmentCharges(strAccountType, waterCharges);
                double srvCharges             = WaterBillManager.CalculateServiceCharges(strAccountType, waterCharges);
                double totalCharges           = waterCharges + sewerCharges + envCharges + srvCharges;
                double localTaxes             = WaterBillManager.CalculateLocalTaxes(strAccountType, waterCharges);
                double stateTaxes             = WaterBillManager.CalculateStateTaxes(strAccountType, waterCharges);
                double amtDue                 = totalCharges + localTaxes + stateTaxes;
    
                txtTotalHCF.Text              = consumption.ToString();
                txtTotalGallons.Text          = ((int)(Math.Ceiling(gallons))).ToString();
                txtFirstTierConsumption.Text  = tiers.first.ToString("F");
                txtSecondTierConsumption.Text = tiers.second.ToString("F");
                txtLastTierConsumption.Text   = tiers.last.ToString("F");
                txtWaterCharges.Text          = waterCharges.ToString("F");
                txtSewerCharges.Text          = sewerCharges.ToString("F");
                txtEnvironmentCharges.Text    = envCharges.ToString("F");
                txtServiceCharges.Text        = srvCharges.ToString("F");
                txtTotalCharges.Text          = totalCharges.ToString("F");
                txtLocalTaxes.Text            = localTaxes.ToString("F");
                txtStateTaxes.Text            = stateTaxes.ToString("F");
                dtpPaymentDueDate.Value       = WaterBillManager.SetPaymentDueDate(strAccountType, dtpMeterReadingEndDate.Value);
                txtAmountDue.Text             = amtDue.ToString("F");
                dtpLatePaymentDueDate.Value   = WaterBillManager.SetLatePaymentDueDate(strAccountType, dtpMeterReadingEndDate.Value);
                txtLateAmountDue.Text         = WaterBillManager.CalculateLateAmountDue(strAccountType, amtDue).ToString("F");
            }
        }
    }

11. Return to the form and double-click the Save Water Bill button
12. Return to the form and double-click the Close button to generate its Click event
13. Implement the events as follows:

    using System.Text.Json;
    using StellarWaterPoint4.Models;
    
    namespace StellarWaterPoint4.WaterBills
    {
        public partial class Create : Form
        {
            public Create()
            {
                InitializeComponent();
            }
    
            private void btnFindCustomerAccount_Click(object sender, EventArgs e)
            {
                if (string.IsNullOrEmpty(mtbAccountNumber.Text))
                {
                    MessageBox.Show("You must type a valid account number of a customer, " +
                                    "and then click the Find Customer Account button.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                string strCustomers = string.Empty;
                List<Customer> clients = new List<Customer>();
                string fileCustomers = @"E:\Stellar Water Point2\Customers.json";
    
                FileInfo fiCustomers = new FileInfo(fileCustomers);
    
                string? strMeterNumber = string.Empty;
    
                if (fiCustomers.Exists == true)
                {
                    using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                    {
                        strCustomers = File.ReadAllText(fiCustomers.FullName);
                        clients = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
    
                        IEnumerable<Customer> customers = clients.Where(cust => cust.AccountNumber == mtbAccountNumber.Text);
    
                        foreach (Customer client in customers)
                        {
                            txtAccountName.Text = client.AccountName;
                            strMeterNumber      = client.MeterNumber;
                            txtAccountType.Text = client.AccountType;
                            txtAddress.Text     = client.Address;
                            txtCity.Text        = client.City;
                            txtCounty.Text      = client.County;
                            txtState.Text       = client.State;
                            txtZIPCode.Text     = client.ZIPCode;
                        }
                    }
                }
    
                if (strMeterNumber!.Length > 0)
                {
                    string strWaterMeters = string.Empty;
                    List<WaterMeter> waterMeters = new List<WaterMeter>();
                    string fileWaterMeters = @"E:\Stellar Water Point2\WaterMeters.json";
    
                    FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
    
                    if (fiWaterMeters.Exists == true)
                    {
                        strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                        waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
    
                        IEnumerable<WaterMeter> meters = waterMeters.Where(wm => wm.MeterNumber == strMeterNumber);
    
                        foreach (WaterMeter meter in meters)
                        {
                            txtMeterDetails.Text = meter.Make + " " +
                                                   meter.Model +
                                                   " (Meter Size: " + meter.MeterSize + ")";
                        }
                    }
                }
            }
    
            private void dtpMeterReadingEndDate_ValueChanged(object sender, EventArgs e)
            {
                TimeSpan tsDays = dtpMeterReadingEndDate.Value - dtpMeterReadingStartDate.Value;
    
                txtBillingDays.Text = (tsDays.Days + 1).ToString();
            }
    
            private void btnEvaluateWaterBill_Click(object sender, EventArgs e)
            {
                double counterStart = 0, counterEnd = 0;
    
                try
                {
                    counterStart = double.Parse(txtCounterReadingStart.Text);
                }
                catch (FormatException feCRStart)
                {
                    MessageBox.Show("You must enter a valid value in the Counter Reading Start text box. " +
                                    "The error produced is: " + feCRStart.Message,
                                    "Stellar Water Point", MessageBoxButtons.OK, MessageBoxIcon.Information);
                }
    
                try
                {
                    counterEnd = double.Parse(txtCounterReadingEnd.Text);
                }
                catch (FormatException feCREnd)
                {
                    MessageBox.Show("You must enter a valid value in the Counter Reading End text box. " +
                                    "The error produced is: " + feCREnd.Message,
                                    "Stellar Water Point", MessageBoxButtons.OK, MessageBoxIcon.Information);
                }
    
                double consumption            = counterEnd - counterStart;
                double gallons                = consumption * 748.05;
                string strAccountType         = txtAccountType.Text[..3];
    
                (double first, double second, double last) tiers = WaterBillManager.CalculateTiers(strAccountType, gallons);
    
                double waterCharges           = tiers.first + tiers.second + tiers.last;
                double sewerCharges           = WaterBillManager.CalculateSewerCharges(strAccountType, waterCharges);
                double envCharges             = WaterBillManager.CalculateEnvironmentCharges(strAccountType, waterCharges);
                double srvCharges             = WaterBillManager.CalculateServiceCharges(strAccountType, waterCharges);
                double totalCharges           = waterCharges + sewerCharges + envCharges + srvCharges;
                double localTaxes             = WaterBillManager.CalculateLocalTaxes(strAccountType, waterCharges);
                double stateTaxes             = WaterBillManager.CalculateStateTaxes(strAccountType, waterCharges);
                double amtDue                 = totalCharges + localTaxes + stateTaxes;
    
                txtTotalHCF.Text              = consumption.ToString();
                txtTotalGallons.Text          = ((int)(Math.Ceiling(gallons))).ToString();
                txtFirstTierConsumption.Text  = tiers.first.ToString("F");
                txtSecondTierConsumption.Text = tiers.second.ToString("F");
                txtLastTierConsumption.Text   = tiers.last.ToString("F");
                txtWaterCharges.Text          = waterCharges.ToString("F");
                txtSewerCharges.Text          = sewerCharges.ToString("F");
                txtEnvironmentCharges.Text    = envCharges.ToString("F");
                txtServiceCharges.Text        = srvCharges.ToString("F");
                txtTotalCharges.Text          = totalCharges.ToString("F");
                txtLocalTaxes.Text            = localTaxes.ToString("F");
                txtStateTaxes.Text            = stateTaxes.ToString("F");
                dtpPaymentDueDate.Value       = WaterBillManager.SetPaymentDueDate(strAccountType, dtpMeterReadingEndDate.Value);
                txtAmountDue.Text             = amtDue.ToString("F");
                dtpLatePaymentDueDate.Value   = WaterBillManager.SetLatePaymentDueDate(strAccountType, dtpMeterReadingEndDate.Value);
                txtLateAmountDue.Text         = WaterBillManager.CalculateLateAmountDue(strAccountType, amtDue).ToString("F");
            }
    
            private void btnSaveWaterBill_Click(object sender, EventArgs e)
            {
                if (string.IsNullOrEmpty(txtBillNumber.Text))
                {
                    MessageBox.Show("You must type a (unique) bill number for the " +
                                    "water bill you are processing.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                if (string.IsNullOrEmpty(mtbAccountNumber.Text))
                {
                    MessageBox.Show("You must specify the account number of the customer " +
                                    "whose water bill you are preparing.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                string strWaterBills      = string.Empty;
                List<WaterBill> bills     = new List<WaterBill>();
                string fileWaterBills     = @"E:\Stellar Water Point2\WaterBills.json";
    
                FileInfo fiWaterBills     = new FileInfo(fileWaterBills);
    
                if (fiWaterBills.Exists   == true)
                {
                    strWaterBills         = File.ReadAllText(fiWaterBills.FullName);
                    bills                 = JsonSerializer.Deserialize<List<WaterBill>>(strWaterBills)!;
                }
    
                WaterBill bill            = new()
                {
                    BillNumber            = int.Parse(txtBillNumber.Text),
                    AccountNumber         = mtbAccountNumber.Text,
                    MeterReadingStartDate = dtpMeterReadingStartDate.Value,
                    MeterReadingEndDate   = dtpMeterReadingEndDate.Value,
                    BillingDays           = int.Parse(txtBillingDays.Text),
                    CounterReadingStart   = int.Parse(txtCounterReadingStart.Text),
                    CounterReadingEnd     = int.Parse(txtCounterReadingEnd.Text),
                    TotalHCF              = int.Parse(txtTotalHCF.Text),
                    TotalGallons          = int.Parse(txtTotalGallons.Text),
                    FirstTierConsumption  = double.Parse(txtFirstTierConsumption.Text),
                    SecondTierConsumption = double.Parse(txtSecondTierConsumption.Text),
                    LastTierConsumption   = double.Parse(txtLastTierConsumption.Text),
                    WaterCharges          = double.Parse(txtWaterCharges.Text),
                    SewerCharges          = double.Parse(txtSewerCharges.Text),
                    EnvironmentCharges    = double.Parse(txtEnvironmentCharges.Text),
                    ServiceCharges        = double.Parse(txtServiceCharges.Text),
                    TotalCharges          = double.Parse(txtTotalCharges.Text),
                    LocalTaxes            = double.Parse(txtLocalTaxes.Text),
                    StateTaxes            = double.Parse(txtStateTaxes.Text),
                    PaymentDueDate        = dtpPaymentDueDate.Value,
                    AmountDue             = double.Parse(txtAmountDue.Text),
                    LatePaymentDueDate    = dtpLatePaymentDueDate.Value,
                    LateAmountDue         = double.Parse(txtLateAmountDue.Text)
                };
    
                bills.Add(bill);
    
                JsonSerializerOptions options = new JsonSerializerOptions();
                options.WriteIndented = true;
    
                string jsWaterBills = JsonSerializer.Serialize(bills, typeof(List<WaterBill>), options);
                File.WriteAllText(fiWaterBills.FullName, jsWaterBills);
    
                Close();
            }
    
            private void btnClose_Click(object sender, EventArgs e)
            {
                Close();
            }
        }
    }

14. In the Solution Explorer, below the WaterBills folder, double-click Central.cs
15. From the Toolbox, add a button to the form below the list view
16. Change the characteristics of the button as follows:

    

    Control		(Name)	Other Properties
    ListView		lvwWaterBills	No Change
    Button		btnProcessWaterBill	&Process Water Bill...

17. On the Central form, double-click the Process Water Bill button
18. Implement the event as follows:

    using System.Data;
    using Microsoft.Data.SqlClient;
    
    namespace StellarWaterPoint31.WaterBills
    {
        public partial class Central : Form
        {
            public Central()
            {
                InitializeComponent();
            }
    
            private void ShowWaterBills()
            {
                . . .
            }
    
            private void Central_Load(object sender, EventArgs e)
            {
                ShowWaterBills();
            }
    
            private void btnProcessWaterBill_Click(object sender, EventArgs e)
            {
                Create create = new();
    
                create.ShowDialog();
    
                ShowWaterBills();
            }
        }
    }

19. To execute the application, on the main menu, click Debug -> Start Without Debugging:

    

20. On the Water Distribution form, click the Water Bills button:

    

21. On the Water Bills form, click the Create Water Bill button:

    

22. Enter the following values in the indicated text boxes or select the date values. Then click Find Customer Account, followed by Evaluate Water Bill, followed by Save Water Bill:

    

    

    Water Bill #	Account #	Reading Start Date	Reading End Date	Counter Reading Start	Counter Reading End
    451474	2068-258-9486	01/11/2010	04/12/2010	103943	103956
    923633	5293-957-3395	01/17/2010	08/18/2010	256945	256972
    917829	9279-570-8394	02/15/2010	05/14/2010	5205	5222
    202666	6986-829-3741	03/08/2010	06/06/2010	5679	5690

    

23. Close the forms and return to your programming environment

Water Bill Details

.

Practical Learning: Showing a Water Bill

1. To create a form, in the Solution Explorer, right-click WaterBills -> Add -> Form (Windows Forms)...
2. For the Name of the form, type Details
3. Press Enter
4. Design the form as follows:

   

   Control		Text	Name	Other Properties
   Label		&Water Bill #:
   TextBox			txtBillNumber
   Button		&Find Water Bill	btnFindWaterBill
   GroupBox		Customer Information
   Label		&Account #:
   TextBox			txtAccountNumber	Enabled: False
   Label		Account Name:
   TextBox			txtAccountName	Enabled: False
   Label		Account Type:
   TextBox			txtAccountType
   Label		Address:		Enabled: False
   TextBox			txtAddress	Enabled: False
   TextBox			txtCity
   TextBox			txtCounty		Enabled: False
   TextBox			txtState	Enabled: False
   TextBox			txtZIPCode	Enabled: False
   Label		_________________________________________________
   Label		Meter Details:
   TextBox			txtMeterDetails	Enabled: False
   GroupBox		Meter Reading
   Label		Meter &Reading Start Date:
   Text Box			txtMeterReadingStartDate	Enabled: False
   Label		Meter Reading &End Date:
   Text Box			txtMeterReadingEndDate	Enabled: False
   Label		Coun&ter Reading Start:
   TextBox			txtCounterReadingStart	Enabled: False
   Label		Counter Readi&ng End:
   TextBox			txtCounterReadingEnd	Enabled: False
   GroupBox		Meter Result
   Label		Billing Days:
   TextBox			txtBillingDays	Enabled: False
   Label		Total HCF:
   TextBox			txtTotalHCF	Enabled: False
   Label		Total Gallons:
   TextBox			txtTotalGallons	Enabled: False
   Label		First Tier Consumption:
   TextBox			txtFirstTierConsumption	Enabled: False
   Label		Second Tier:
   TextBox			txtSecondTierConsumption	Enabled: False
   Label		Last Tier:
   TextBox			txtLastTierConsumption	Enabled: False
   GroupBox		Consumption Charges
   Label		Water Charges:
   TextBox			txtWaterCharges	Enabled: False
   Label		Sewer Charges:
   TextBox			txtSewerCharges	Enabled: False
   Label		Environment Charges:
   TextBox			txtEnvironmentCharges	Enabled: False
   Label		Service Charges:
   TextBox			txtServiceCharges	Enabled: False
   Label		Total Charges:
   TextBox			txtTotalCharges	Enabled: False
   GroupBox		Taxes
   Label		Local Taxes:
   TextBox			txtLocalTaxes	Enabled: False
   Label		State Taxes:
   TextBox			txtStateTaxes	Enabled: False
   GroupBox		Water Bill Payment
   Label		Payment Due Date:
   Date Time Picker			dtpPaymentDueDate	Enabled: False
   Label		Amount Due:
   TextBox			txtAmountDue	Enabled: False
   Label		Late Payment Due Date:
   Text Box			txtLatePaymentDueDate	Enabled: False
   Label		&Late Amount Due:
   TextBox			txtLateAmountDue
   Button		&Close	btnClose

   Form Properties

   Form Property	Value
   FormBorderStyle	FixedDialog
   Text	Stellar Water Point - Water Bill Processing
   StartPosition	CenterScreen
   MaximizeBox	False
   MinimizeBox	False

5. On the form, double-click the Find Water Bill button
6. Return to the form and double-click the Close button
7. Change the document as follows:

   using System.Text.Json;
   using StellarWaterPoint4.Models;
   
   namespace StellarWaterPoint4.WaterBills
   {
       public partial class Details : Form
       {
           public Details()
           {
               InitializeComponent();
           }
   
           private void btnFindWaterBill_Click(object sender, EventArgs e)
           {
               string strWaterBills = string.Empty;
               // Prepare a bills list to hold the records of water bills
               List<WaterBill> bills = new List<WaterBill>();
               // Specify the file that holds the records of water bills
               string fileWaterBills = @"E:\Stellar Water Point2\WaterBills.json";
   
               // Create a FileInfo object for the records of water bills
               FileInfo fiWaterBills = new FileInfo(fileWaterBills);
   
               // Find out whether a file that holds the records of water bills exists already
               if (fiWaterBills.Exists == true)
               {
                   // If that file exists, create a TextReader object to read the file
                   using (TextReader trWaterBills = new StreamReader(fiWaterBills.FullName))
                   {
                       /* Read the contents of the file that holds the water bills.
                        * Store the read text in the strWaterBills variable that was declared. */
                       strWaterBills = File.ReadAllText(fiWaterBills.FullName);
                       // Get the water bills and store them in the bills list variable
                       bills = JsonSerializer.Deserialize<List<WaterBill>>(strWaterBills)!;
   
                       IEnumerable<WaterBill> selected = bills.Where(wb => wb.BillNumber == int.Parse(txtBillNumber.Text));
   
                       foreach (var bill in selected)
                       {
                           txtAccountNumber.Text = bill.AccountNumber;
                           txtMeterReadingStartDate.Text = bill.MeterReadingStartDate.ToLongDateString();
                           txtMeterReadingEndDate.Text = bill.MeterReadingEndDate.ToLongDateString();
                           txtBillingDays.Text = bill.BillingDays.ToString();
                           txtCounterReadingStart.Text = bill.CounterReadingStart.ToString();
                           txtCounterReadingEnd.Text = bill.CounterReadingEnd.ToString();
                           txtTotalHCF.Text = bill.TotalHCF.ToString();
                           txtTotalGallons.Text = bill.TotalGallons.ToString();
                           txtFirstTierConsumption.Text = bill.FirstTierConsumption.ToString();
                           txtSecondTierConsumption.Text = bill.SecondTierConsumption.ToString();
                           txtLastTierConsumption.Text = bill.LastTierConsumption.ToString();
                           txtWaterCharges.Text = bill.WaterCharges.ToString();
                           txtSewerCharges.Text = bill.SewerCharges.ToString();
                           txtEnvironmentCharges.Text = bill.EnvironmentCharges.ToString();
                           txtServiceCharges.Text = bill.ServiceCharges.ToString();
                           txtTotalCharges.Text = bill.TotalCharges.ToString();
                           txtLocalTaxes.Text = bill.LocalTaxes.ToString();
                           txtStateTaxes.Text = bill.StateTaxes.ToString();
                           txtPaymentDueDate.Text = bill.PaymentDueDate.ToLongDateString();
                           txtAmountDue.Text = bill.AmountDue.ToString();
                           txtLatePaymentDueDate.Text = bill.LatePaymentDueDate.ToLongDateString();
                           txtLateAmountDue.Text = bill.LateAmountDue.ToString();
                       }
                   }
               }
   
               string strCustomers = string.Empty;
               List<Customer> clients = new List<Customer>();
               string fileCustomers = @"E:\Stellar Water Point2\Customers.json";
   
               FileInfo fiCustomers = new FileInfo(fileCustomers);
   
               string? strMeterNumber = string.Empty;
   
               if (fiCustomers.Exists == true)
               {
                   using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                   {
                       strCustomers = File.ReadAllText(fiCustomers.FullName);
                       clients = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
   
                       IEnumerable<Customer> customers = from consumer
                                                         in clients
                                                         where consumer.AccountNumber == txtAccountNumber.Text
                                                         select consumer;
   
                       foreach (Customer client in customers)
                       {
                           txtAccountName.Text = client.AccountName;
                           strMeterNumber = client.MeterNumber;
                           txtAccountType.Text = client.AccountType;
                           txtAddress.Text = client.Address;
                           txtCity.Text = client.City;
                           txtCounty.Text = client.County;
                           txtState.Text = client.State;
                           txtZIPCode.Text = client.ZIPCode;
                       }
                   }
               }
   
               if (strMeterNumber!.Length > 0)
               {
                   string strWaterMeters = string.Empty;
                   List<WaterMeter> waterMeters = new List<WaterMeter>();
                   string fileWaterMeters = @"E:\Stellar Water Point2\WaterMeters.json";
   
                   FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
   
                   if (fiWaterMeters.Exists == true)
                   {
                       strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                       waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
   
                       IEnumerable<WaterMeter> meters = from measure
                                                        in waterMeters
                                                        where measure.MeterNumber == strMeterNumber
                                                        select measure;
   
                       foreach (WaterMeter meter in waterMeters)
                       {
                           txtMeterDetails.Text = meter.Make + " " +
                                                  meter.Model +
                                                  " (Meter Size: " + meter.MeterSize + ")";
                       }
                   }
               }
           }
   
           private void btnClose_Click(object sender, EventArgs e)
           {
               Close();
           }
       }
   }

8. In the Solution Explorer, below the WaterBills folder, double-click Central.cs to open its form
9. From the Toolbox, add a button to the form below the list view and to the right of the New Water Bill button
10. Change the characteristics of the button as follows:

    

    Control		(Name)	Other Properties
    ListView		lvwWaterBills	No Change
    Button		No Change	No Change
    Button		btnWaterBillDetails	Water Bill &Details... Anchor: Bottom, Right

11. Double-click the Water Bill &Details button
12. Change the document as follows:

    using System.Data;
    using Microsoft.Data.SqlClient;
    
    namespace StellarWaterPoint31.WaterBills
    {
        public partial class Central : Form
        {
            public Central()
            {
                InitializeComponent();
            }
    
            private void ShowWaterBills()
            {
                . . .
            }
    
            private void Central_Load(object sender, EventArgs e)
            {
                ShowWaterBills();
            }
    
            private void btnProcessWaterBill_Click(object sender, EventArgs e)
            {
                Create create = new();
    
                create.ShowDialog();
    
                ShowWaterBills();
            }
    
            private void btnViewWaterBill_Click(object sender, EventArgs e)
            {
                Details details = new();
    
                details.Show();
            }
        }
    }

13. To execute the application, on the main menu, click Debug -> Start Without Debugging

    

14. On the Water Distribution form, click the Water Bills button:

    

15. On the Water Bills form, click the View Water Bill button:

    

16. In the Water Bill # text box, type 917829

    

17. Click the Find Water Bill button:

    

18. Close the forms and return to your programming environment

Water Bill Edition

.

Practical Learning: Creating a Water Bill Editor

1. In the Solution Explorer, right-click the WaterBills folder -> Add -> Form (Windows Forms...)
2. Set the name of the form to Editor
3. Click Add
4. Using the Properties window, change the size of the new form to match the size of the Process Water Bill form
5. Select everything in the Process Water Bill form and copy it
6. Paste it in Water Bill Editor form
7. Change the design of the Water Bill Editor form as follows (you will add only the controls that are not found in the New Water Bill form):

   

   Control		(Name)	Text	Additional Properties
   Button		btnFindWaterBill	&Find
   Button		btnUpdateWaterBill	&Update Water Bill

8. On the form, double-click Find Water Bill button
9. Change the document as follows:

   using StellarWaterPoint4.Models;
   using System.Text.Json;
   
   namespace StellarWaterPoint4.WaterBills
   {
       public partial class Editor : Form
       {
           public Editor()
           {
               InitializeComponent();
           }
   
           private void btnFindWaterBill_Click(object sender, EventArgs e)
           {
               string strWaterBills = string.Empty;
               List<WaterBill> bills = new List<WaterBill>();
               string fileWaterBills = @"E:\Stellar Water Point2\WaterBills.json";
   
               FileInfo fiWaterBills = new FileInfo(fileWaterBills);
   
               if (fiWaterBills.Exists == true)
               {
                   using (TextReader trWaterBills = new StreamReader(fiWaterBills.FullName))
                   {
                       strWaterBills = File.ReadAllText(fiWaterBills.FullName);
                       bills = JsonSerializer.Deserialize<List<WaterBill>>(strWaterBills)!;
   
                       IEnumerable<WaterBill> selected = bills.Where(wb => wb.BillNumber == int.Parse(txtBillNumber.Text));
   
                       foreach (var bill in selected)
                       {
                           mtbAccountNumber.Text = bill.AccountNumber;
                           dtpMeterReadingStartDate.Value = bill.MeterReadingStartDate;
                           dtpMeterReadingEndDate.Value = bill.MeterReadingEndDate;
                           txtBillingDays.Text = bill.BillingDays.ToString();
                           txtCounterReadingStart.Text = bill.CounterReadingStart.ToString();
                           txtCounterReadingEnd.Text = bill.CounterReadingEnd.ToString();
                           txtTotalHCF.Text = bill.TotalHCF.ToString();
                           txtTotalGallons.Text = bill.TotalGallons.ToString();
                           txtFirstTierConsumption.Text = bill.FirstTierConsumption.ToString();
                           txtSecondTierConsumption.Text = bill.SecondTierConsumption.ToString();
                           txtLastTierConsumption.Text = bill.LastTierConsumption.ToString();
                           txtWaterCharges.Text = bill.WaterCharges.ToString();
                           txtSewerCharges.Text = bill.SewerCharges.ToString();
                           txtEnvironmentCharges.Text = bill.EnvironmentCharges.ToString();
                           txtServiceCharges.Text = bill.ServiceCharges.ToString();
                           txtTotalCharges.Text = bill.TotalCharges.ToString();
                           txtLocalTaxes.Text = bill.LocalTaxes.ToString();
                           txtStateTaxes.Text = bill.StateTaxes.ToString();
                           dtpPaymentDueDate.Value = bill.PaymentDueDate;
                           txtAmountDue.Text = bill.AmountDue.ToString();
                           dtpLatePaymentDueDate.Value = bill.LatePaymentDueDate;
                           txtLateAmountDue.Text = bill.LateAmountDue.ToString();
                       }
                   }
               }
   
               string strCustomers = string.Empty;
               List<Customer> clients = new List<Customer>();
               string fileCustomers = @"E:\Stellar Water Point2\Customers.json";
   
               FileInfo fiCustomers = new FileInfo(fileCustomers);
   
               string? strMeterNumber = string.Empty;
   
               if (fiCustomers.Exists == true)
               {
                   using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                   {
                       strCustomers = File.ReadAllText(fiCustomers.FullName);
                       clients = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
   
                       IEnumerable<Customer> customers = from consumer
                                                         in clients
                                                         where consumer.AccountNumber == mtbAccountNumber.Text
                                                         select consumer;
   
                       foreach (Customer client in customers)
                       {
                           txtAccountName.Text = client.AccountName;
                           strMeterNumber = client.MeterNumber;
                           txtAccountType.Text = client.AccountType;
                           txtAddress.Text = client.Address;
                           txtCity.Text = client.City;
                           txtCounty.Text = client.County;
                           txtState.Text = client.State;
                           txtZIPCode.Text = client.ZIPCode;
                       }
                   }
               }
   
               if (strMeterNumber!.Length > 0)
               {
                   string strWaterMeters = string.Empty;
                   List<WaterMeter> waterMeters = new List<WaterMeter>();
                   string fileWaterMeters = @"E:\Stellar Water Point2\WaterMeters.json";
   
                   FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
   
                   if (fiWaterMeters.Exists == true)
                   {
                       strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                       waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
   
                       IEnumerable<WaterMeter> meters = from measure
                                                        in waterMeters
                                                        where measure.MeterNumber == strMeterNumber
                                                        select measure;
   
                       foreach (WaterMeter meter in waterMeters)
                       {
                           txtMeterDetails.Text = meter.Make + " " +
                                                  meter.Model +
                                                  " (Meter Size: " + meter.MeterSize + ")";
                       }
                   }
               }
           }
       }
   }

10. Return to the form and double-click the Find Customer Account button
11. Implement the event as follows:

    using StellarWaterPoint4.Models;
    using System.Text.Json;
    
    namespace StellarWaterPoint4.WaterBills
    {
        public partial class Editor : Form
        {
            public Editor()
            {
                InitializeComponent();
            }
    
            private void btnFindWaterBill_Click(object sender, EventArgs e)
            {
                . . .
            }
    
            private void btnFindCustomerAccount_Click(object sender, EventArgs e)
            {
                if (string.IsNullOrEmpty(mtbAccountNumber.Text))
                {
                    MessageBox.Show("You must type a valid account number of a customer, " +
                                    "and then click the Find Customer Account button.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                string strCustomers = string.Empty;
                List<Customer> clients = new List<Customer>();
                string fileCustomers = @"E:\Stellar Water Point2\Customers.json";
    
                FileInfo fiCustomers = new FileInfo(fileCustomers);
    
                string? strMeterNumber = string.Empty;
    
                if (fiCustomers.Exists == true)
                {
                    using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                    {
                        strCustomers = File.ReadAllText(fiCustomers.FullName);
                        clients = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
    
                        IEnumerable<Customer> customers = clients.Where(cust => cust.AccountNumber == mtbAccountNumber.Text);
    
                        foreach (Customer client in customers)
                        {
                            txtAccountName.Text = client.AccountName;
                            strMeterNumber = client.MeterNumber;
                            txtAccountType.Text = client.AccountType;
                            txtAddress.Text = client.Address;
                            txtCity.Text = client.City;
                            txtCounty.Text = client.County;
                            txtState.Text = client.State;
                            txtZIPCode.Text = client.ZIPCode;
                        }
                    }
                }
    
                if (strMeterNumber!.Length > 0)
                {
                    string strWaterMeters = string.Empty;
                    List<WaterMeter> waterMeters = new List<WaterMeter>();
                    string fileWaterMeters = @"E:\Stellar Water Point2\WaterMeters.json";
    
                    FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
    
                    if (fiWaterMeters.Exists == true)
                    {
                        strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                        waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
    
                        IEnumerable<WaterMeter> meters = waterMeters.Where(wm => wm.MeterNumber == strMeterNumber);
    
                        foreach (WaterMeter meter in meters)
                        {
                            txtMeterDetails.Text = meter.Make + " " +
                                                   meter.Model +
                                                   " (Meter Size: " + meter.MeterSize + ")";
                        }
                    }
                }
            }
        }
    }

12. Return to the form and double-click the Meter Reading End Date date time picker control
13. Implement the event as follows:

    using System.Data;
    using Microsoft.Data.SqlClient;
    
    namespace StellarWaterPoint31.WaterBills
    {
        public partial class Editor : Form
        {
            public Editor()
            {
                InitializeComponent();
            }
    
            private void btnFindWaterBill_Click(object sender, EventArgs e)
            {
                . . .
            }
    
            private void btnFindCustomerAccount_Click(object sender, EventArgs e)
            {
                . . .
            }
    
            private void dtpMeterReadingEndDate_ValueChanged(object sender, EventArgs e)
            {
                TimeSpan tsDays = dtpMeterReadingEndDate.Value - dtpMeterReadingStartDate.Value;
    
                txtBillingDays.Text = (tsDays.Days + 1).ToString();
            }
        }
    }

14. Return to the form and double-click the Evaluate Water Bill button
15. Implement the event as follows:

    using StellarWaterPoint4.Models;
    using System.Text.Json;
    
    namespace StellarWaterPoint4.WaterBills
    {
        public partial class Editor : Form
        {
            public Editor()
            {
                InitializeComponent();
            }
    
            private void btnFindWaterBill_Click(object sender, EventArgs e)
            {
                . . .
            }
    
            private void btnFindCustomerAccount_Click(object sender, EventArgs e)
            {
                . . .
            }
    
            private void dtpMeterReadingEndDate_ValueChanged(object sender, EventArgs e)
            {
                TimeSpan tsDays = dtpMeterReadingEndDate.Value - dtpMeterReadingStartDate.Value;
    
                txtBillingDays.Text = (tsDays.Days + 1).ToString();
            }
    
            private void btnEvaluateWaterBill_Click(object sender, EventArgs e)
            {
                double counterStart = 0, counterEnd = 0;
    
                try
                {
                    counterStart = double.Parse(txtCounterReadingStart.Text);
                }
                catch (FormatException feCRStart)
                {
                    MessageBox.Show("You must enter a valid value in the Counter Reading Start text box. " +
                                    "The error produced is: " + feCRStart.Message,
                                    "Stellar Water Point", MessageBoxButtons.OK, MessageBoxIcon.Information);
                }
    
                try
                {
                    counterEnd = double.Parse(txtCounterReadingEnd.Text);
                }
                catch (FormatException feCREnd)
                {
                    MessageBox.Show("You must enter a valid value in the Counter Reading End text box. " +
                                    "The error produced is: " + feCREnd.Message,
                                    "Stellar Water Point", MessageBoxButtons.OK, MessageBoxIcon.Information);
                }
    
                double consumption = counterEnd - counterStart;
                double gallons = consumption * 748.05;
                string strAccountType = txtAccountType.Text[..3];
    
                (double first, double second, double last) tiers = WaterBillManager.CalculateTiers(strAccountType, gallons);
    
                double waterCharges = tiers.first + tiers.second + tiers.last;
                double sewerCharges = WaterBillManager.CalculateSewerCharges(strAccountType, waterCharges);
                double envCharges = WaterBillManager.CalculateEnvironmentCharges(strAccountType, waterCharges);
                double srvCharges = WaterBillManager.CalculateServiceCharges(strAccountType, waterCharges);
                double totalCharges = waterCharges + sewerCharges + envCharges + srvCharges;
                double localTaxes = WaterBillManager.CalculateLocalTaxes(strAccountType, waterCharges);
                double stateTaxes = WaterBillManager.CalculateStateTaxes(strAccountType, waterCharges);
                double amtDue = totalCharges + localTaxes + stateTaxes;
    
                txtTotalHCF.Text = consumption.ToString();
                txtTotalGallons.Text = ((int)(Math.Ceiling(gallons))).ToString();
                txtFirstTierConsumption.Text = tiers.first.ToString("F");
                txtSecondTierConsumption.Text = tiers.second.ToString("F");
                txtLastTierConsumption.Text = tiers.last.ToString("F");
                txtWaterCharges.Text = waterCharges.ToString("F");
                txtSewerCharges.Text = sewerCharges.ToString("F");
                txtEnvironmentCharges.Text = envCharges.ToString("F");
                txtServiceCharges.Text = srvCharges.ToString("F");
                txtTotalCharges.Text = totalCharges.ToString("F");
                txtLocalTaxes.Text = localTaxes.ToString("F");
                txtStateTaxes.Text = stateTaxes.ToString("F");
                dtpPaymentDueDate.Value = WaterBillManager.SetPaymentDueDate(strAccountType, dtpMeterReadingEndDate.Value);
                txtAmountDue.Text = amtDue.ToString("F");
                dtpLatePaymentDueDate.Value = WaterBillManager.SetLatePaymentDueDate(strAccountType, dtpMeterReadingEndDate.Value);
                txtLateAmountDue.Text = WaterBillManager.CalculateLateAmountDue(strAccountType, amtDue).ToString("F");
            }
        }
    }

16. Return to the form and double-click the Update Water Bill button
17. Return to the form and double-click the Close button
18. Change the document as follows:

       
                    
    Close();

19. In the Solution Explorer, below the WaterBills folder, double-click Central.cs
20. From the Toolbox, add a button to the form below the list view and on the right side of the View Water Bill button
21. Change the characteristics of the button as follows:

    

    Control		(Name)	Text	Other Properties
    ListView		lvwWaterBills		No Change
    Button		btnNewWaterBill		No Change
    Button		btnViewWaterBill		No Change
    Button		btnEditWaterBill	&Edit Water Bill...	Anchor: Bottom, Right

22. Double-click the Edit Water Bill button
23. Implement the event as follows:

    using System.Data;
    using Microsoft.Data.SqlClient;
    
    namespace StellarWaterPoint31.WaterBills
    {
        public partial class Central : Form
        {
            public Central()
            {
                InitializeComponent();
            }
    
            private void ShowWaterBills()
            {
                . . .
            }
    
            private void Central_Load(object sender, EventArgs e)
            {
                ShowWaterBills();
            }
    
            private void btnProcessWaterBill_Click(object sender, EventArgs e)
            {
                Create create = new();
    
                create.ShowDialog();
    
                ShowWaterBills();
            }
    
            private void btnViewWaterBill_Click(object sender, EventArgs e)
            {
                Details details = new();
    
                details.Show();
            }
    
            private void btnEditWaterBill_Click(object sender, EventArgs e)
            {
                
            }
        }
    }

24. To execute the application, on the main menu, click Debug -> Start Without Debugging

    

25. On the main form of the application, click the Customers button:

    

26. Click the Edit Water Bill button:

    

27. In the Water Bill # text, type 923633
28. Click the Find Water Bill button

    

29. Change the following values:

    Account #:                9249-379-6848 and click Find Customer Account
    Meter Reading Start Date: 1/19/2010
    Meter Reading End Date:   4/17/2010
    Counter Reading Start:    256953
    Counter Reading End:      256966

30. Click the Evaluate Water Bill button:

    

31. Click the Update Water Bill button and click OK on the message box:

    

32. Close the forms and return to your programming environment

Water Bill Deletion

.

Practical Learning: Editing/Updating a Record

1. To create a form, in the Solution Explorer, right-click the WaterBills folder -> Add -> Form (Windows Forms...)
2. Change the file Name to Delete
Click Add Resize the form to have the same size as the Water Bill Details form
3. Select and copy everything in the Water Bill Details form
4. Paste it in the new Water Bill Delete form
5. Change the design of the form as follows (you will add only one button):

   

   Control		(Name)	Text
   Button		btnDeleteWaterBill	&Delete Water Bill

6. On the form, double-click the Find Water Bill button
7. Change the document as follows:

   using System.Text.Json;
   using StellarWaterPoint4.Models;
   
   namespace StellarWaterPoint4.WaterBills
   {
       public partial class Delete : Form
       {
           public Delete()
           {
               InitializeComponent();
           }
   
           private void btnFindWaterBill_Click(object sender, EventArgs e)
           {
               string strWaterBills = string.Empty;
               List<WaterBill> bills = new List<WaterBill>();
               string fileWaterBills = @"E:\Stellar Water Point2\WaterBills.json";
   
               FileInfo fiWaterBills = new FileInfo(fileWaterBills);
   
               if (fiWaterBills.Exists == true)
               {
                   using (TextReader trWaterBills = new StreamReader(fiWaterBills.FullName))
                   {
                       strWaterBills = File.ReadAllText(fiWaterBills.FullName);
                       bills = JsonSerializer.Deserialize<List<WaterBill>>(strWaterBills)!;
   
                       IEnumerable<WaterBill> selected = bills.Where(wb => wb.BillNumber == int.Parse(txtBillNumber.Text));
   
                       foreach (var bill in selected)
                       {
                           txtAccountNumber.Text = bill.AccountNumber;
                           txtMeterReadingStartDate.Text = bill.MeterReadingStartDate.ToLongDateString();
                           txtMeterReadingEndDate.Text = bill.MeterReadingEndDate.ToLongDateString();
                           txtBillingDays.Text = bill.BillingDays.ToString();
                           txtCounterReadingStart.Text = bill.CounterReadingStart.ToString();
                           txtCounterReadingEnd.Text = bill.CounterReadingEnd.ToString();
                           txtTotalHCF.Text = bill.TotalHCF.ToString();
                           txtTotalGallons.Text = bill.TotalGallons.ToString();
                           txtFirstTierConsumption.Text = bill.FirstTierConsumption.ToString();
                           txtSecondTierConsumption.Text = bill.SecondTierConsumption.ToString();
                           txtLastTierConsumption.Text = bill.LastTierConsumption.ToString();
                           txtWaterCharges.Text = bill.WaterCharges.ToString();
                           txtSewerCharges.Text = bill.SewerCharges.ToString();
                           txtEnvironmentCharges.Text = bill.EnvironmentCharges.ToString();
                           txtServiceCharges.Text = bill.ServiceCharges.ToString();
                           txtTotalCharges.Text = bill.TotalCharges.ToString();
                           txtLocalTaxes.Text = bill.LocalTaxes.ToString();
                           txtStateTaxes.Text = bill.StateTaxes.ToString();
                           txtPaymentDueDate.Text = bill.PaymentDueDate.ToLongDateString();
                           txtAmountDue.Text = bill.AmountDue.ToString();
                           txtLatePaymentDueDate.Text = bill.LatePaymentDueDate.ToLongDateString();
                           txtLateAmountDue.Text = bill.LateAmountDue.ToString();
                       }
                   }
               }
   
               string strCustomers = string.Empty;
               List<Customer> clients = new List<Customer>();
               string fileCustomers = @"E:\Stellar Water Point2\Customers.json";
   
               FileInfo fiCustomers = new FileInfo(fileCustomers);
   
               string? strMeterNumber = string.Empty;
   
               if (fiCustomers.Exists == true)
               {
                   using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                   {
                       strCustomers = File.ReadAllText(fiCustomers.FullName);
                       clients = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
   
                       IEnumerable<Customer> customers = from consumer
                                                         in clients
                                                         where consumer.AccountNumber == txtAccountNumber.Text
                                                         select consumer;
   
                       foreach (Customer client in customers)
                       {
                           txtAccountName.Text = client.AccountName;
                           strMeterNumber = client.MeterNumber;
                           txtAccountType.Text = client.AccountType;
                           txtAddress.Text = client.Address;
                           txtCity.Text = client.City;
                           txtCounty.Text = client.County;
                           txtState.Text = client.State;
                           txtZIPCode.Text = client.ZIPCode;
                       }
                   }
               }
   
               if (strMeterNumber!.Length > 0)
               {
                   string strWaterMeters = string.Empty;
                   List<WaterMeter> waterMeters = new List<WaterMeter>();
                   string fileWaterMeters = @"E:\Stellar Water Point2\WaterMeters.json";
   
                   FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
   
                   if (fiWaterMeters.Exists == true)
                   {
                       strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                       waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
   
                       IEnumerable<WaterMeter> meters = from measure
                                                        in waterMeters
                                                        where measure.MeterNumber == strMeterNumber
                                                        select measure;
   
                       foreach (WaterMeter meter in waterMeters)
                       {
                           txtMeterDetails.Text = meter.Make + " " +
                                                  meter.Model +
                                                  " (Meter Size: " + meter.MeterSize + ")";
                       }
                   }
               }
           }
       }
   }

8. Return to the form and double-click the Delete Water Bill button
9. Return to the form and double-click the Close button
10. Change the document as follows:

    using System.Text.Json;
    using StellarWaterPoint4.Models;
    
    namespace StellarWaterPoint4.WaterBills
    {
        public partial class Delete : Form
        {
            public Delete()
            {
                InitializeComponent();
            }
    
            private void btnFindWaterBill_Click(object sender, EventArgs e)
            {
                string strWaterBills = string.Empty;
                // Prepare a bills list to hold the records of water bills
                List<WaterBill> bills = new List<WaterBill>();
                // Specify the file that holds the records of water bills
                string fileWaterBills = @"E:\Stellar Water Point2\WaterBills.json";
    
                // Create a FileInfo object for the records of water bills
                FileInfo fiWaterBills = new FileInfo(fileWaterBills);
    
                // Find out whether a file that holds the records of water bills exists already
                if (fiWaterBills.Exists == true)
                {
                    // If that file exists, create a TextReader object to read the file
                    using (TextReader trWaterBills = new StreamReader(fiWaterBills.FullName))
                    {
                        /* Read the contents of the file that holds the water bills.
                         * Store the read text in the strWaterBills variable that was declared. */
                        strWaterBills = File.ReadAllText(fiWaterBills.FullName);
                        // Get the water bills and store them in the bills list variable
                        bills = JsonSerializer.Deserialize<List<WaterBill>>(strWaterBills)!;
    
                        IEnumerable<WaterBill> selected = bills.Where(wb => wb.BillNumber == int.Parse(txtBillNumber.Text));
    
                        foreach (var bill in selected)
                        {
                            txtAccountNumber.Text = bill.AccountNumber;
                            txtMeterReadingStartDate.Text = bill.MeterReadingStartDate.ToLongDateString();
                            txtMeterReadingEndDate.Text = bill.MeterReadingEndDate.ToLongDateString();
                            txtBillingDays.Text = bill.BillingDays.ToString();
                            txtCounterReadingStart.Text = bill.CounterReadingStart.ToString();
                            txtCounterReadingEnd.Text = bill.CounterReadingEnd.ToString();
                            txtTotalHCF.Text = bill.TotalHCF.ToString();
                            txtTotalGallons.Text = bill.TotalGallons.ToString();
                            txtFirstTierConsumption.Text = bill.FirstTierConsumption.ToString();
                            txtSecondTierConsumption.Text = bill.SecondTierConsumption.ToString();
                            txtLastTierConsumption.Text = bill.LastTierConsumption.ToString();
                            txtWaterCharges.Text = bill.WaterCharges.ToString();
                            txtSewerCharges.Text = bill.SewerCharges.ToString();
                            txtEnvironmentCharges.Text = bill.EnvironmentCharges.ToString();
                            txtServiceCharges.Text = bill.ServiceCharges.ToString();
                            txtTotalCharges.Text = bill.TotalCharges.ToString();
                            txtLocalTaxes.Text = bill.LocalTaxes.ToString();
                            txtStateTaxes.Text = bill.StateTaxes.ToString();
                            txtPaymentDueDate.Text = bill.PaymentDueDate.ToLongDateString();
                            txtAmountDue.Text = bill.AmountDue.ToString();
                            txtLatePaymentDueDate.Text = bill.LatePaymentDueDate.ToLongDateString();
                            txtLateAmountDue.Text = bill.LateAmountDue.ToString();
                        }
                    }
                }
    
                string strCustomers = string.Empty;
                List<Customer> clients = new List<Customer>();
                string fileCustomers = @"E:\Stellar Water Point2\Customers.json";
    
                FileInfo fiCustomers = new FileInfo(fileCustomers);
    
                string? strMeterNumber = string.Empty;
    
                if (fiCustomers.Exists == true)
                {
                    using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                    {
                        strCustomers = File.ReadAllText(fiCustomers.FullName);
                        clients = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
    
                        IEnumerable<Customer> customers = from consumer
                                                          in clients
                                                          where consumer.AccountNumber == txtAccountNumber.Text
                                                          select consumer;
    
                        foreach (Customer client in customers)
                        {
                            txtAccountName.Text = client.AccountName;
                            strMeterNumber = client.MeterNumber;
                            txtAccountType.Text = client.AccountType;
                            txtAddress.Text = client.Address;
                            txtCity.Text = client.City;
                            txtCounty.Text = client.County;
                            txtState.Text = client.State;
                            txtZIPCode.Text = client.ZIPCode;
                        }
                    }
                }
    
                if (strMeterNumber!.Length > 0)
                {
                    string strWaterMeters = string.Empty;
                    List<WaterMeter> waterMeters = new List<WaterMeter>();
                    string fileWaterMeters = @"E:\Stellar Water Point2\WaterMeters.json";
    
                    FileInfo fiWaterMeters = new FileInfo(fileWaterMeters);
    
                    if (fiWaterMeters.Exists == true)
                    {
                        strWaterMeters = File.ReadAllText(fiWaterMeters.FullName);
                        waterMeters = JsonSerializer.Deserialize<List<WaterMeter>>(strWaterMeters)!;
    
                        IEnumerable<WaterMeter> meters = from measure
                                                         in waterMeters
                                                         where measure.MeterNumber == strMeterNumber
                                                         select measure;
    
                        foreach (WaterMeter meter in waterMeters)
                        {
                            txtMeterDetails.Text = meter.Make + " " +
                                                   meter.Model +
                                                   " (Meter Size: " + meter.MeterSize + ")";
                        }
                    }
                }
            }
    
            private void btnDeleteWaterBill_Click(object sender, EventArgs e)
            {
                if (string.IsNullOrEmpty(txtBillNumber.Text))
                {
                    MessageBox.Show("Please provide the bill number of the water bill you want to delete, " +
                                    "and then click the Find Water Bill button.",
                                    "Stellar Water Point", MessageBoxButtons.OK);
                    return;
                }
    
                string strWaterBills = string.Empty;
                List<WaterBill> waterBills = new List<WaterBill>();
                string fileWaterBills = @"E:\Stellar Water Point2\WaterBills.json";
    
                FileInfo fiWaterBills = new FileInfo(fileWaterBills);
    
                if (fiWaterBills.Exists == true)
                {
                    strWaterBills = File.ReadAllText(fiWaterBills.FullName);
                    waterBills = JsonSerializer.Deserialize<List<WaterBill>>(strWaterBills)!;
    
                    WaterBill bill = waterBills.Find(bl => bl.BillNumber == int.Parse(txtBillNumber.Text))!;
    
                    if (bill is not null)
                    {
                        if (MessageBox.Show("Are you sure you want to delete (or remove) or cancel " +
                                          "this water bill from the system (you cannot undo the action)?",
                                          "Stellar Water Point",
                                          MessageBoxButtons.YesNo,
                                          MessageBoxIcon.Information) == DialogResult.Yes)
                        {
                            waterBills.Remove(bill);
    
                            JsonSerializerOptions options = new JsonSerializerOptions();
                            options.WriteIndented = true;
    
                            string jsWaterBills = JsonSerializer.Serialize(waterBills, typeof(List<WaterBill>), options);
                            File.WriteAllText(fiWaterBills.FullName, jsWaterBills);
    
                            MessageBox.Show("The water bill has been deleted (or removed, or cancelled) from our system.",
                                          "Stellar Water Point", MessageBoxButtons.OK, MessageBoxIcon.Information);
                        }
                    }
                }
    
                Close();
            }
    
            private void btnClose_Click(object sender, EventArgs e)
            {
                Close();
            }
        }
    }

11. In the Solution Explorer, below the WaterBills folder, double-click Central.cs to open its form
12. From the Toolbox, add two buttons to the form below the list view and to the right of the Edit Water Bill button
13. Change the form design as follows:

    

    Control		(Name)	Text	Other Properties
    ListView		lvwWaterBills		Anchor: Bottom, Top, Bottom, Left, Right
    Button		btnProcessWaterBill	&Process Water Bill...	Anchor: Bottom, Right
    Button		btnViewWaterBill	&View Water Bill...	Anchor: Bottom, Right
    Button		btnEditWaterBill	&Edit Water Bill...	Anchor: Bottom, Right
    Button		btnDeleteWaterBill	&Delete Water Bill...	Anchor: Bottom, Right
    Button		btnClose	&Close	Anchor: Bottom, Right

14. On the form, double-click the Delete Water Bill button
15. Return to the Water Bills - Central form and double-click the Close button
16. Implement the events as follows:

    using System.Text.Json;
    using StellarWaterPoint4.Models;
    
    namespace StellarWaterPoint4.WaterBills
    {
        public partial class Central : Form
        {
            public Central()
            {
                InitializeComponent();
            }
    
            private void ShowWaterBills()
            {
                // We will need the list of customers to display an account summary in the list view
                // Declare a strCustomers variable that will hold the records from the JSON file
                string strCustomers = string.Empty;
                // Prepare a list to hold the records of customers
                List<Customer> clients = new List<Customer>();
                // Specify the file that holds the records of customers
                string fileCustomers = @"E:\Stellar Water Point2\Customers.json";
    
                // Create a FileInfo object for the records of customers
                FileInfo fiCustomers = new FileInfo(fileCustomers);
    
                // Check if a file that holds the records of customers was created already
                if (fiCustomers.Exists == true)
                {
                    // If that file exists, create a TextReader object to get those records
                    using (TextReader trCustomers = new StreamReader(fiCustomers.FullName))
                    {
                        // Read the records and store them in the strCustomers variable
                        strCustomers = File.ReadAllText(fiCustomers.FullName);
                        // Use JSON deserialization to get the records of customers
                        clients = JsonSerializer.Deserialize<List<Customer>>(strCustomers)!;
                    }
                }
    
                // Declare a strWaterBills variable that will hold the records from the JSON file
                string strWaterBills = string.Empty;
                // Prepare a bills list to hold the records of water bills
                List<WaterBill> bills = new List<WaterBill>();
                // Specify the file that holds the records of water bills
                string fileWaterBills = @"E:\Stellar Water Point2\WaterBills.json";
    
                // Create a FileInfo object for the records of water bills
                FileInfo fiWaterBills = new FileInfo(fileWaterBills);
    
                // Find out whether a file that holds the records of water bills exists already
                if (fiWaterBills.Exists == true)
                {
                    // If that file exists, create a TextReader object to read the file
                    using (TextReader trWaterBills = new StreamReader(fiWaterBills.FullName))
                    {
                        /* Read the contents of the file that holds the water bills.
                         * Store the read text in the strWaterBills variable that was declared. */
                        strWaterBills = File.ReadAllText(fiWaterBills.FullName);
                        // Get the water bills and store them in the bills list variable
                        bills = JsonSerializer.Deserialize<List<WaterBill>>(strWaterBills)!;
    
                        // This variable will be used to keep count of the water bills records
                        int counter = 1;
    
                        /* We are about to display the water bills records in the list view.
                         * Before proceeding, first remove any record in the list view. */
                        lvwWaterBills.Items.Clear();
    
                        // Visit each record of the water bills
                        foreach (WaterBill client in bills)
                        {
                            /* Prepare a ListViewItem object for each record.
                             * Display the record counter in the first column of this object. */
                            ListViewItem lviWaterBill = new ListViewItem(counter++.ToString());
    
                            // Display the water bill number of the current record
                            lviWaterBill.SubItems.Add(client.BillNumber.ToString());
    
                            /* Refer to the list of records of the customers (that list was prepared earlier).
                             * Use LINQ to get the customer whose account number is 
                             * the same as the account number of the current record. */
                            IEnumerable<Customer> customer = clients.Where(cust => cust.AccountNumber == client.AccountNumber);
    
                            // Now that we have located the customer record, display some details about it
                            foreach (Customer cust in customer)
                            {
                                lviWaterBill.SubItems.Add(client.AccountNumber + " - " +
                                                          cust.AccountName +
                                                          ", Type: " + cust.AccountType![..3] +
                                                          ", (Mtr #: " + cust.MeterNumber + ")");
                            }
    
                            /* Continue displaying some other parts of the water bill.
                             * Before there is not enough space for the whole water bill, we display only some values. */
                            lviWaterBill.SubItems.Add(client.MeterReadingStartDate.ToShortDateString());
                            lviWaterBill.SubItems.Add(client.MeterReadingEndDate.ToShortDateString());
                            lviWaterBill.SubItems.Add(client.BillingDays.ToString());
                            lviWaterBill.SubItems.Add(client.CounterReadingStart.ToString());
                            lviWaterBill.SubItems.Add(client.CounterReadingEnd.ToString());
                            lviWaterBill.SubItems.Add(client.TotalHCF.ToString());
                            lviWaterBill.SubItems.Add(client.TotalGallons.ToString());
                            lviWaterBill.SubItems.Add(client.PaymentDueDate.ToShortDateString());
                            lviWaterBill.SubItems.Add(client.AmountDue.ToString());
    
                            lvwWaterBills.Items.Add(lviWaterBill);
                        }
                    }
                }
            }
    
            private void Central_Load(object sender, EventArgs e)
            {
                ShowWaterBills();
            }
    
            private void btnProcessWaterBill_Click(object sender, EventArgs e)
            {
                Create create = new();
    
                create.ShowDialog();
    
                ShowWaterBills();
            }
    
            private void btnViewWaterBill_Click(object sender, EventArgs e)
            {
                Details details = new();
    
                details.Show();
            }
    
            private void btnEditWaterBill_Click(object sender, EventArgs e)
            {
                Editor editor = new();
    
                editor.ShowDialog();
    
                ShowWaterBills();
            }
    
            private void btnDeleteWaterBill_Click(object sender, EventArgs e)
            {
                Delete delete = new();
    
                delete.ShowDialog();
    
                ShowWaterBills();
            }
    
            private void btnClose_Click(object sender, EventArgs e)
            {
                Close();
            }
        }
    }

17. To execute, on the main menu, click Debug -> Start Without Debugging:

    

18. On the Stellar Water Point form, click the Water Bills button

    

19. On the Water Bills form, click the Delete Water Bill button

    

20. In the Water Bill # text box, type 917829

    

21. Click Find Water Bill

    

22. Click Delete Water Bill
23. Read the message in the message box and click Yes:

    

24. Close the forms and return to your programming environment
25. Close Microsoft Visual Studio

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