Setting Up the Application

Introduction

Serialization consists of saving one or more values to a computer stream. An example is to save an object, an instance of a class. This characteristic allows you to create a text-based database. For an example, we will create an application for a company that sells automobile parts and other accessories.

Practical Learning: Introducing the Application

1. On the C: drive (or any drive of your choice) of your computer, create a folder or directory named College Park Auto-Parts (if you create it in another drive, make the changes wherever "C:\College Park Auto-Parts" is used in this project)
2. Save the following image in that folder:

   

3. Save the following icons to your computer: , , , , , , , , ,
4. Start Microsoft Visual Studio
5. Create a new Windows Forms App named CollegeParkAutoParts1
6. In the Solution Explorer, right-click the name of the project -> Add -> Folder
7. Type Models as the name of the folder and press Enter
8. To create a class, in the Solution Explorer, right-click Models -> Add -> Class...
9. Type MsgBox as the name of the file and class
10. Click Add
11. Change the class as follows:

    namespace CollegeParkAutoParts2.Models
    {
        public enum Answer { No = 0, Yes = 1, Cancel = 2, Unknown = 3 }
    
        internal static class MsgBox
        {
            public static void Regular(string message)
            {
                MessageBox.Show(message,
                                "College Park Auto-Parts",
                                MessageBoxButtons.OK,
                                MessageBoxIcon.Information);
            }
    
            public static Answer Question(string message)
            {
                DialogResult result = MessageBox.Show(message,
                                                      "College Park Auto-Parts",
                                                      MessageBoxButtons.YesNoCancel,
                                                      MessageBoxIcon.Question);
    
                switch (result)
                {
                    case DialogResult.Yes:
                        return Answer.Yes;
                    case DialogResult.No:
                        return Answer.No;
                    case DialogResult.Cancel:
                        return Answer.Cancel;
                    default:
                        return Answer.Unknown;
                }
            }
        }
    }

Parts Manufacturers

The company for which we are building the application sells automobile parts. The primary piece of information you should provide for an automobile part is the manufacturer. In this section, we will create that can allow an employee to create a name for a manufacturer.

Practical Learning: Introducing Parts Manufacturers

1. To create a dialog box, on the main menu, click Project -> Add Form (Windows Forms)...
2. Set the name to Make
3. Click Add
4. Design the form as follows:

   

   Control		Text	Name	Other Properties
   Label		&Make:
   TextBox			txtMake	Modifiers: Public
   Button		&OK	btnOK	DialogResult: OK
   Button		&Cancel	btnCancel	DialogResult: Cancel

   Form Characteristics

   Form Property	Value
   FormBorderStyle	FixedDialog
   Text	Make
   StartPosition	CenterScreen
   AcceptButton	btnOK
   CancelButton	btnCancel
   MaximizeBox	False
   MinimizeBox	False
   ShowInTaskbar	False

Parts Models

The second valuable piece of information you should provide about an object sold in a store is the model. In this section, we will create a form that an employee can use to provide that information.

Practical Learning: Introducing Parts Models

1. To create a dialog box, on the main menu, click Project -> Add Form (Windows Forms)...
2. Set the name to Model
3. Click Add
4. Design the form as follows:

   

   Control		Text	Name	Other Properties
   Label		&Model:
   TextBox			txtModel	Modifiers: Public
   Button		&OK	btnOK	DialogResult: OK
   Button		&Cancel	btnCancel	DialogResult: Cancel

   Form Characteristics

   Form Property	Value
   FormBorderStyle	FixedDialog
   Text	Category Editor
   StartPosition	CenterScreen
   AcceptButton	btnOK
   CancelButton	btnCancel
   MaximizeBox	False
   MinimizeBox	False
   ShowInTaskbar	False

Parts Categories

A company can make objects that use the same model but some options can different items of the same model. To allow a user to provide such information, we will create a form.

Practical Learning: Introducing Parts Categories

1. To create a dialog box, on the main menu, click Project -> Add Form (Windows Forms)...
2. Set the name to Category
3. Click Add
4. Design the form as follows:

   

   Control		Text	Name	Other Properties
   Label		C&ategory:
   TextBox			txtCategory	Modifiers: Public
   Button		&OK	btnOK	DialogResult: OK
   Button		&Cancel	btnCancel	DialogResult: Cancel

   Form Characteristics

   Form Property	Value
   FormBorderStyle	FixedDialog
   Text	Category
   StartPosition	CenterScreen
   AcceptButton	btnOK
   CancelButton	btnCancel
   MaximizeBox	False
   MinimizeBox	False
   ShowInTaskbar	False

A Class for Auto-Parts

To keep our application simple, we will conside that the business is mainly selling only automobile parts. Each part will be represented by some characteristics that we will list in a class.

Practical Learning: Creating a Class for Auto-Parts

1. To create a class, in the Solution Explorer, right-click Models -> Add -> Class...
2. Type AutoPart as the name of the file and class
3. Click Add
4. Change the class as follows:

   namespace CollegeParkAutoParts2.Models
   {
       public class AutoPart
       {
           public long    PartNumber  { set; get; }
           public int     Year        { set; get; }
           public string? Make        { get; set; }
           public string? Model       { get; set; } 
           public string? Category    { get; set; }  
           public string? PartName    { get; set; }
           public double  UnitPrice   { get; set; }
           public string? PictureFile { get; set; }
       }
   }

A New Store Item

A store item is an object that a store sells. When it comes to a company that sells automobile parts, the employees must create records for what the company is selling. For that reason, we will create a form that can be used to create records for the items sold in the store.

Practical Learning: Creating an Auto-Part

1. To add a new form, on the main menu, click Project -> Add Form (Windows Forms)...
2. Set the Name to StoreItemNew
3. Click Add
4. Design the form as follows:

   

   Control		(Name)	Text	Other Properties
   Label			&Part #:
   Text Box		txtPartNumber
   Button		btnSelectPicture	&Select Picture...
   Label		lblPictureFile	.
   Label			&Year:
   Combo Box		cbxYears
   Picture Box		pbxPartImage		BorderStyle: FixedSingle: SizeMode: AutoSize
   Label			&Make:
   Combo Box		cbxMakes
   Button		btnNewMake	New M&ke...
   Label			M&odel:
   Combo Box		cbxModels
   Button			New Mo&del
   Label			Ca&tegory:
   Combo Box		cbxCategories
   Button		btnNewCategory	New Cat&egory...
   Label			Part Na&me:
   Text Box		txtPartName		ScrollBars: Vertical Multiline: True
   Label			&Unit Price
   Text Box		txtUnitPrice
   Label			_________________
   Button		btnSaveAutoPart	Sa&ve Auto-Part
   Button		btnClose	&Close
   OpenFileDialog		ofdPictureFile

5. Click an unoccupied area of the form and, in the Properties window, change the following characteristics:
   Text: College Park Auto-Parts - New Store Item
   MaximizeBox: False
   ShowInTaskbar: False
   StartPosition: CenterScreen
6. Double-click an unoccupied area of the form to generate its Load event
7. Change the document as follows:

   using CollegeParkAutoParts2.Models;
   using System.Xml.Serialization;
   
   namespace CollegeParkAutoParts2
   {
       public partial class StoreItemNew : Form
       {
           List<AutoPart> AutoParts { get; set; } = new List<AutoPart>();
   
           public StoreItemNew()
           {
               InitializeComponent();
           }
   
           private void InitializeAutoParts()
           {
               string strFileName = @"C:\College Park Auto-Parts\AutoParts.xml";
               XmlSerializer xsAutoParts = new XmlSerializer(typeof(List<AutoPart>));
   
               for (int year = DateTime.Today.Year + 1; year >= DateTime.Today.Year - 20; year--)
                   cbxYears.Items.Add(year);
   
               if (File.Exists(strFileName))
               {
                   Random rndNumber = new();
   
                   cbxMakes.Items.Clear();
                   cbxModels.Items.Clear();
                   cbxCategories.Items.Clear();
                   txtPartName.Text = string.Empty;
                   txtUnitPrice.Text = string.Empty;
                   txtPartNumber.Text = rndNumber.Next(100000, 999999).ToString();
   
                   using (FileStream fsAutoParts = new FileStream(strFileName,
                                                                   FileMode.Open,
                                                                   FileAccess.Read,
                                                                   FileShare.Read))
                   {
                       AutoParts = (List<AutoPart>)xsAutoParts.Deserialize(fsAutoParts)!;
   
                       for (int i = 0; i < AutoParts.Count; i++)
                       {
                           if (!cbxMakes.Items.Contains(AutoParts[i].Make))
                               cbxMakes.Items.Add(AutoParts[i].Make!);
                       }
   
                       for (int i = 0; i < AutoParts.Count; i++)
                       {
                           if (!cbxCategories.Items.Contains(AutoParts[i].Category))
                               cbxCategories.Items.Add(AutoParts[i].Category!);
                       }
                   }
               }
   
               lblPictureFile.Text = @"C:\College Park Auto-Parts\Generic.png";
               pbxPartImage.Image = Image.FromFile(@"C:\College Park Auto-Parts\Generic.png");
   
               Width = pbxPartImage.Right + 40;
               Height = pbxPartImage.Bottom + 75;
           }
   
           private void StoreItemNew_Load(object sender, EventArgs e)
           {
               InitializeAutoParts();
           }
       }
   }

8. Return to the form and double-click the Select Picture button
9. Implement the event as follows:

   private void btnSelectPicture_Click(object sender, EventArgs e)
   {
       if (ofdPictureFile.ShowDialog() == DialogResult.OK)
       {
           lblPictureFile.Text = ofdPictureFile.FileName;
           pbxPartImage.Image = Image.FromFile(ofdPictureFile.FileName);
       }
       else
       {
           pbxPartImage.Image = Image.FromFile(@"C:\College Park Auto-Parts1\Generic.png");
       }
   
       Width = pbxPartImage.Right + 40;
       Height = pbxPartImage.Bottom + 75;
   }

10. Return to the form and double-click the Makes combo box to generate its Selected Index event
11. Implement the event as follows:

    private void cbxMakes_SelectedIndexChanged(object sender, EventArgs e)
    {
        cbxModels.Items.Clear();
        cbxModels.Text = string.Empty;
    
        foreach (AutoPart part in AutoParts)
        {
            if (part.Make == cbxMakes.Text)
            {
                if (!cbxModels.Items.Contains(part.Model))
                {
                    cbxModels.Items.Add(part.Model!);
                }
            }
        }
    }

12. Return to the form and double-click the New Make button
13. Implement the event as follows:

    private void btnNewMake_Click(object sender, EventArgs e)
    {
        Make editor = new Make();
    
        if (editor.ShowDialog() == DialogResult.OK)
        {
            if (editor.txtMake.Text.Length > 0)
            {
                string strMake = editor.txtMake.Text;
    
                if (cbxMakes.Items.Contains(strMake))
                {
                    MsgBox.Regular(strMake + " is already in the list.");
                }
                else
                {
                    cbxMakes.Items.Add(strMake);
                }
    
                cbxMakes.Text = strMake;
            }
        }
    }

14. Return to the form and double-click the New Model button
15. Implement the event as follows:

    private void btnNewModel_Click(object sender, EventArgs e)
    {
        Model editor = new();
    
        if (editor.ShowDialog() == DialogResult.OK)
        {
            if (editor.txtModel.Text.Length > 0)
            {
                string strModel = editor.txtModel.Text;
    
                if (cbxModels.Items.Contains(strModel))
                {
                    MsgBox.Regular(strModel + " is already in the list.");
                }
                else
                {
                    cbxModels.Items.Add(strModel);
                }
    
                cbxModels.Text = strModel;
            }
        }
    }

16. Return to the form and double-click the New Category button
17. Implement the event as follows:

    private void btnNewCategory_Click(object sender, EventArgs e)
    {
        var editor = new Category();
    
        if (editor.ShowDialog() == DialogResult.OK)
        {
            if (editor.txtCategory.Text.Length > 0)
            {
                string strCategory = editor.txtCategory.Text;
    
                if (cbxCategories.Items.Contains(strCategory))
                {
                    MsgBox.Regular(strCategory + " is already in the list.");
                }
                else
                {
                    cbxCategories.Items.Add(strCategory);
                }
    
                cbxCategories.Text = strCategory;
            }
        }
    }

18. Return to the form and double-click the Save Auto Part button
19. Return to the form and double-click the Close button
20. Change the document as follows:

    using CollegeParkAutoParts2.Models;
    using System.Xml.Serialization;
    
    namespace CollegeParkAutoParts2
    {
        public partial class StoreItemNew : Form
        {
            /* This property is used to hold the list of auto-parts of our application.
             * (We didn't have to use a global variable. We could have used local variables.) */
            List<AutoPart> AutoParts { get; set; } = new List<AutoPart>();
    
            public StoreItemNew()
            {
                InitializeComponent();
            }
    
            /* This function is used to reset the form.
             * It can be called when necessary. */
            private void InitializeAutoParts()
            {
                // This file is the repository of our database
                string strFileName = @"C:\College Park Auto-Parts1\AutoParts.xml";
                // We will use XML serialization to manage the records of our database
                XmlSerializer xsAutoParts = new XmlSerializer(typeof(List<AutoPart>));
    
                cbxYears.Items.Clear();
                
                /* Show the years in the top combo box.
                 * We will consider only the cars made in the last 20 years. */
                for (int year = DateTime.Today.Year + 1; year >= DateTime.Today.Year - 20; year--)
                {
                    cbxYears.Items.Add(year);
                }
    
                // Check whether the file that holds the store inventory was created already
                if (File.Exists(strFileName))
                {
                    cbxMakes.Items.Clear();
                    cbxModels.Items.Clear();
                    cbxCategories.Items.Clear();
                    txtPartName.Text   = string.Empty;
                    txtUnitPrice.Text  = string.Empty;
                    txtPartNumber.Text = string.Empty;
    
                    // If the inventory file exists, open it
                    using (FileStream fsAutoParts = new FileStream(strFileName,
                                                                   FileMode.Open,
                                                                   FileAccess.Read,
                                                                   FileShare.Read))
                    {
                        // Retrieve the list of items from file
                        AutoParts = (List<AutoPart>)xsAutoParts.Deserialize(fsAutoParts)!;
    
                        // Display the cars manufacturers in the combo box
                        for (int i = 0; i < AutoParts.Count; i++)
                        {
                            // Make sure the list box doesn't yet have the category being added
                            if (!cbxMakes.Items.Contains(AutoParts[i].Make))
                            {
                                cbxMakes.Items.Add(AutoParts[i].Make!);
                            }
                        }
    
                        // Display the categories in the box
                        for (int i = 0; i < AutoParts.Count; i++)
                        {
                            // Make sure the list box doesn't yet have the category being added
                            if (!cbxCategories.Items.Contains(AutoParts[i].Category))
                            {
                                cbxCategories.Items.Add(AutoParts[i].Category!);
                            }
                        }
                    }
                }
    
                lblPictureFile.Text = @"C:\College Park Auto-Parts1\Generic.png";
                pbxPartImage.Image  = Image.FromFile(@"C:\College Park Auto-Parts1\Generic.png");
    
                Width               = pbxPartImage.Right + 40;
                Height              = pbxPartImage.Bottom + 75;
            }
    
            private void StoreItemNew_Load(object sender, EventArgs e)
            {
                InitializeAutoParts();
            }
    
            private void btnSelectPicture_Click(object sender, EventArgs e)
            {
                if (ofdPictureFile.ShowDialog() == DialogResult.OK)
                {
                    lblPictureFile.Text = ofdPictureFile.FileName;
                    pbxPartImage.Image = Image.FromFile(ofdPictureFile.FileName);
                }
                else
                {
                    pbxPartImage.Image = Image.FromFile(@"C:\College Park Auto-Parts1\Generic.png");
                }
    
                Width = pbxPartImage.Right + 40;
                Height = pbxPartImage.Bottom + 75;
            }
    
            private void cbxMakes_SelectedIndexChanged(object sender, EventArgs e)
            {
                cbxModels.Text = "";
                cbxModels.Items.Clear();
    
                foreach (AutoPart part in AutoParts)
                {
                    if (part.Make == cbxMakes.Text)
                    {
                        if (!cbxModels.Items.Contains(part.Model))
                        {
                            cbxModels.Items.Add(part.Model!);
                        }
                    }
                }
            }
    
            private void btnNewMake_Click(object sender, EventArgs e)
            {
                Make editor = new Make();
    
                if (editor.ShowDialog() == DialogResult.OK)
                {
                    if (editor.txtMake.Text.Length > 0)
                    {
                        string strMake = editor.txtMake.Text;
    
                        // Make sure the manufacturer is not yet in the list
                        if (cbxMakes.Items.Contains(strMake))
                        {
                            MsgBox.Regular(strMake + " is already in the list.");
                        }
                        else
                        {
                            // Since this is a new category, add it to the combo box
                            cbxMakes.Items.Add(strMake);
                        }
    
                        cbxMakes.Text = strMake;
                    }
                }
            }
    
            private void btnNewModel_Click(object sender, EventArgs e)
            {
                Model editor = new();
    
                if (editor.ShowDialog() == DialogResult.OK)
                {
                    if (editor.txtModel.Text.Length > 0)
                    {
                        string strModel = editor.txtModel.Text;
    
                        // Make sure the category is not yet in the list
                        if (cbxModels.Items.Contains(strModel))
                        {
                            MsgBox.Regular(strModel + " is already in the list.");
                        }
                        else
                        {
                            // Since this is a new category, add it to the combo box
                            cbxModels.Items.Add(strModel);
                        }
    
                        cbxModels.Text = strModel;
                    }
                }
            }
    
            private void btnNewCategory_Click(object sender, EventArgs e)
            {
                var editor = new Category();
    
                if (editor.ShowDialog() == DialogResult.OK)
                {
                    if (editor.txtCategory.Text.Length > 0)
                    {
                        string strCategory = editor.txtCategory.Text;
    
                        // Make sure the category is not yet in the list
                        if (cbxCategories.Items.Contains(strCategory))
                        {
                            MsgBox.Regular(strCategory + " is already in the list.");
                        }
                        else
                        {
                            // Since this is a new category, add it to the combo box
                            cbxCategories.Items.Add(strCategory);
                        }
    
                        cbxCategories.Text = strCategory;
                    }
                }
            }
    
            private void btnSaveAutoPart_Click(object sender, EventArgs e)
            {
                // Make sure the user had selected a year
                if (string.IsNullOrEmpty(cbxYears.Text))
                {
                    MsgBox.Regular("You must specify the year.");
                    return;
                }
    
                // Make sure the user had selected a make
                if (string.IsNullOrEmpty(cbxMakes.Text))
                {
                    MsgBox.Regular("You must specify the car name.");
                    return;
                }
    
                // Make sure the user had selected a model
                if (string.IsNullOrEmpty(cbxModels.Text))
                {
                    MsgBox.Regular("You must specify the model of the car.");
                    return;
                }
    
                // Make sure the user had entered a name/description
                if (string.IsNullOrEmpty(txtPartName.Text))
                {
                    MsgBox.Regular("You must enter the name (or a " +
                                    "short description) for the part.");
                    txtPartName.Focus();
                    return;
                }
    
                // Make sure the user had typed a price for the item
                if (string.IsNullOrEmpty(txtUnitPrice.Text))
                {
                    MsgBox.Regular("You must enter the price of the item.");
                    txtUnitPrice.Focus();
                    return;
                }
    
                string strFileName = @"C:\College Park Auto-Parts1\AutoParts.xml";
                XmlSerializer xsAutoParts = new XmlSerializer(typeof(List<AutoPart>));
    
                if (File.Exists(strFileName))
                {
                    // If the inventory file exists, open it
                    using (FileStream fsAutoParts = new(strFileName, FileMode.Open,
                                                        FileAccess.Read, FileShare.Read))
                    {
                        // Retrieve the list of items from file
                        AutoParts = (List<AutoPart>)xsAutoParts.Deserialize(fsAutoParts)!;
                    }
                }
    
                AutoPart part    = new AutoPart();
    
                part.PartNumber  =   long.Parse(txtPartNumber.Text);
                part.Year        =    int.Parse(cbxYears.Text);
                part.Make        =              cbxMakes.Text;
                part.Model       =              cbxModels.Text;
                part.Category    =              cbxCategories.Text;
                part.PartName    =              txtPartName.Text;
                part.UnitPrice   = double.Parse(txtUnitPrice.Text);
                part.PictureFile =              lblPictureFile.Text;
    
                // Call the Add method of our collection class to add the part
                AutoParts.Add(part);
    
                TextWriter twAutoParts = new StreamWriter(strFileName);
                xsAutoParts.Serialize(twAutoParts, AutoParts);
                twAutoParts.Close();
    
                InitializeAutoParts();
            }
    
            private void btnClose_Click(object sender, EventArgs e)
            {
                Close();
            }
        }
    }

Application Design

Our application will have a central form from which all the regular operations are performed. To start, we will design it to show the user interface that will allow the employees to interact with the application.

Practical Learning: Designing the Application

1. In the Solution Explorer, right-click Form1.cs -> Rename
2. Type StoreInventory (to get StoreInventory.cs) and press Enter three times to display the form
3. From the Components section of the Toolbox, click ImageList and click the form
4. In the Properties window, click (Name) and type ilAutoParts
5. Click the ellipsis button of the Images field
6. In the Image Collection Editor, click Add
7. Select the following icons you had saved in your computer: Sign1, Sign2, Cliper1, Cliper2, Rulers1, Rulers2, Graph1, Graph2, Tool1, and Tool2
8. Click Open

   

9. Click OK
10. Design the form as follows:

    

    Control		(Name)	Text	Other Properties
    Label			College Park Auto-Parts	Font: Times New Roman, 24pt, style=Bold ForeColor: Blue
    PictureBox				BackColor: Black Size -> Height: 5
    GroupBox			Part Identification
    TreeView		tvwAutoParts		ImageList: AutoPartsImages
    GroupBox			Available Parts
    ListView		lvwAvailableParts		View: Details FullRowSelect: True GridLines: True
    Columns	(Name) Text TextAlign Width colAvailablePartNumber Part #   80 colAvailablePartName Part Name/Description   650 colAvailableUnitPrice Unit Price Right 100
    PictureBox		pbxPartImage		BorderStyle: FixedSingle SizeMode: AutoSize
    GroupBox			Selected Parts
    Label			Part #
    Label			Part Name
    Label			Unit Price
    Label			Qty
    Label			Sub-Total
    Text Box			txtPartNumber
    Text Box		txtPartName
    Text Box		txtUnitPrice		TextAlign: Right
    Text Box		txtQuantity		TextAlign: Right
    Text Box		txtSubTotal		TextAlign: Right
    Button		btnAdd	Add/Select
    ListView			lvwSelectedParts	View: Details FullRowSelect: True GridLines: True
    Columns	(Name) Text TextAlign Width colSelectedPartNumber Part #   80 colSelectedPartName Part Name/Description   600 colSelectedUnitPrice Unit Price Right 100 colSelectedQuantity Qty Right 50 colSelectedSubTotal Sub-Total Right 90
    GroupBox			Order Summary
    Button		btnNewAutoPart	New Auto Part...
    Label			Selected Parts Total:
    Text Box		txtSelectedPartsTotal		TextAlign: Right
    Label			Tax Rate:
    Text Box		txtTaxRate		TextAlign: Right
    Label			Tax Amount:
    Text Box		txtTaxAmount		TextAlign: Right
    Label			Order Total:
    Text Box		txtOrderTotal		TextAlign: Right

11. Double-click an unoccupied area of the form
12. Change the document as follows:

    using System.Xml.Serialization;
    
    namespace CollegeParkAutoParts
    {
        public partial class StoreInvetory : Form
        {
            /* We will need a list of auto-parts.
             * For demonstration purpose, we are creating the list as a property
             * (but a global list is not necessary; we could have used local list variables).*/
            public List<AutoPart> AutoParts { get; set; } = new List<AutoPart>();
    
            public StoreInvetory()
            {
                InitializeComponent();
            }
    
            // This function is used to reset the form
            void InitializeAutoParts()
            {
                // When the form must be reset, removes all nodes from the tree view
                tvwAutoParts.Nodes.Clear();
                // Create the root node of the tree view
                TreeNode nodRoot = tvwAutoParts.Nodes.Add("College Park Auto-Parts",
                                                          "College Park Auto-Parts", 0, 1);
                /* Add the cars years to the tree view.
                 * Our application will deal only with the cars in the last 21 years. */
                for (int years = DateTime.Today.Year + 1; years >= DateTime.Today.Year - 20; years--)
                    nodRoot.Nodes.Add(years.ToString(), years.ToString(), 2, 3);
    
                // Select the root node
                tvwAutoParts.SelectedNode = nodRoot;
                // Expand the root node
                tvwAutoParts.ExpandAll();
    
                // AutoParts = new List<AutoPart>();
    
                // This is the file that holds the list of auto parts
                string strFileName = @"C:\College Park Auto-Parts\AutoParts.xml";
                XmlSerializer xsAutoParts = new(typeof(List<AutoPart>));
    
                if (File.Exists(strFileName))
                {
                    // If the inventory file exists, open it
                    using (FileStream fsAutoParts = new FileStream(strFileName,
                                                                    FileMode.Open,
                                                                    FileAccess.Read,
                                                                    FileShare.Read))
                    {
                        // Retrieve the list of items from file
                        AutoParts = (List<AutoPart>)xsAutoParts.Deserialize(fsAutoParts)!;
    
                        // Show the makes nodes
                        foreach (TreeNode nodYear in nodRoot.Nodes)
                        {
                            List<string> lstMakes = new List<string>();
    
                            foreach (AutoPart part in AutoParts)
                            {
                                if (nodYear.Text == part.Year.ToString())
                                {
                                    if (!lstMakes.Contains(part.Make!))
                                        lstMakes.Add(part.Make!);
                                }
                            }
    
                            foreach (string strMake in lstMakes)
                                nodYear.Nodes.Add(strMake, strMake, 4, 5);
                        }
    
                        // Showing the models nodes
                        foreach (TreeNode nodYear in nodRoot.Nodes)
                        {
                            foreach (TreeNode nodMake in nodYear.Nodes)
                            {
                                List<string> lstModels = new List<string>();
    
                                foreach (AutoPart part in AutoParts)
                                {
                                    if( (nodYear.Text == part.Year.ToString() ) &
                                        (nodMake.Text == part.Make))
                                    {
                                        if (!lstModels.Contains(part.Model!))
                                            lstModels.Add(part.Model!);
                                    }
                                }
    
                                foreach (string strModel in lstModels)
                                    nodMake.Nodes.Add(strModel, strModel, 6, 7);
                            }
                        }
    
                        // Showing the categories nodes
                        foreach (TreeNode nodYear in nodRoot.Nodes)
                        {
                            foreach (TreeNode nodMake in nodYear.Nodes)
                            {
                                foreach (TreeNode nodModel in nodMake.Nodes)
                                {
                                    List<string> lstCategories = new List<string>();
    
                                    foreach (AutoPart part in AutoParts)
                                    {
    
                                        if ((nodYear.Text  == part.Year.ToString()) &
                                            (nodMake.Text  == part.Make) &
                                            (nodModel.Text == part.Model))
                                        {
                                            if (!lstCategories.Contains(part.Category!))
                                                lstCategories.Add(part.Category!);
                                        }
                                    }
    
                                    foreach (string strCategory in lstCategories)
                                        nodModel.Nodes.Add(strCategory, strCategory, 8, 9);
                                }
                            }
                        }
                    }
                }
    
                lvwSelectedParts.Items.Clear();
                lvwAvailableParts.Items.Clear();
                txtTaxRate.Text            = string.Empty;
                txtPartName.Text           = string.Empty;
                txtQuantity.Text           = string.Empty;
                txtSubTotal.Text           = string.Empty;
                txtUnitPrice.Text          = string.Empty;
                txtTaxAmount.Text          = string.Empty;
                txtOrderTotal.Text         = string.Empty;
                txtPartNumber.Text         = string.Empty;
                txtSelectedPartsTotal.Text = string.Empty;
                pbxPartImage.Image         = Image.FromFile(@"C:\College Park Auto-Parts\Generic.png");
    
                Width = pbxPartImage.Right + 40;
            }
    
            private void StoreInvetory_Load(object sender, EventArgs e)
            {
                InitializeAutoParts();
            }
        }
    }

13. Return to the Store Inventory form and click the Available Parts list view
14. In the Properties window, click the Events button
15. In the Events section of the Properties window for the Available Parts list view, double-click ItemSelectionChanged
16. Implement the event as follows:

    private void lvwAvailableParts_ItemSelectionChanged(object sender, ListViewItemSelectionChangedEventArgs e)
    {
        bool pictureFound = false;
        string strFileName = @"C:\College Park Auto-Parts1\AutoParts.xml";
        XmlSerializer xsAutoParts = new XmlSerializer(typeof(List<AutoPart>));
    
        if (File.Exists(strFileName))
        {
            using (FileStream fsAutoParts = new FileStream(strFileName,
                                                           FileMode.Open,
                                                           FileAccess.Read,
                                                           FileShare.Read))
            {
                AutoParts = (List<AutoPart>)xsAutoParts.Deserialize(fsAutoParts)!;
    
                foreach (AutoPart part in AutoParts)
                {
                    if (part.PartNumber == long.Parse(e.Item!.SubItems[0].Text))
                    {
                        pictureFound = true;
                        pbxPartImage.Image = Image.FromFile(part.PictureFile!);
                        break;
                    }
                }
            }
        }
    
        if (pictureFound == false)
        {
            pbxPartImage.Image = Image.FromFile(@"C:\College Park Auto-Parts1\Generic.png");
        }
    
        Width = pbxPartImage.Right + 40;
        Height = pbxPartImage.Bottom + 75;
    }

17. Return to the Store Inventory form and make sure the Available Parts list view is still selected
18. In the Events section of the Properties window, double-click DoubleClick
19. Implement the event as follows:

    private void lvwAvailableParts_DoubleClick(object sender, EventArgs e)
    {
        ListViewItem lviAutoPart = lvwAvailableParts.SelectedItems[0];
    
        if ((lvwAvailableParts.SelectedItems.Count == 0) ||
            (lvwAvailableParts.SelectedItems.Count > 1))
            return;
    
        txtPartNumber.Text = lviAutoPart.Text;
        txtPartName.Text = lviAutoPart.SubItems[1].Text;
        txtUnitPrice.Text = lviAutoPart.SubItems[2].Text;
    
        txtQuantity.Text = "1";
        txtSubTotal.Text = lviAutoPart.SubItems[2].Text;
    
        txtQuantity.Focus();
    }

20. Return to the Store Inventory form and click the Unit Price text box
21. In the Events section of the Properties window, double-click Leave
22. Implement the event as follows:

    private void txtUnitPrice_Leave(object sender, EventArgs e)
    {
        double subTotal;
        double unitPrice = 0D;
        double quantity = 0.00d;
    
        try
        {
            unitPrice = double.Parse(txtUnitPrice.Text);
        }
        catch (FormatException)
        {
            MsgBox.Regular("Invalid Unit Price!");
        }
    
        try
        {
            quantity = int.Parse(txtQuantity.Text);
        }
        catch (FormatException)
        {
            MsgBox.Regular("Invalid Quandtity!");
        }
    
        subTotal = unitPrice * quantity;
        txtSubTotal.Text = subTotal.ToString("F");
    }

23. Return to the Store Inventory form and click the Qty text box
24. In the Events section of the Properties window, click Leave, then click the arrow of that field and select txtUnitPrice_Leave
25. On the Store Inventory form, click the Part # text box
26. In the Events section of the Properties window, double-click Leave
27. Implement the event as follows:

    private void txtPartNumber_Leave(object sender, EventArgs e)
    {
        bool found = false;
    
        foreach (AutoPart part in AutoParts)
        {
            if (part.PartNumber == long.Parse(txtPartNumber.Text))
            {
                txtPartName.Text = part.PartName;
                txtUnitPrice.Text = part.UnitPrice.ToString("F");
    
                if (string.IsNullOrEmpty(txtQuantity.Text))
                    txtQuantity.Text = "1";
    
                txtSubTotal.Text = part.UnitPrice.ToString("F");
    
                txtQuantity.Focus();
    
                found = true;
                break;
            }
        }
    
        if (found == false)
        {
            txtPartName.Text = "";
            txtUnitPrice.Text = "0.00";
            txtQuantity.Text = "0";
            txtSubTotal.Text = "0.00";
    
            MsgBox.Regular("There is no part with that number.");
        }
    }

28. Return to the Store Inventory form and double-click the Add/Select button
29. Implement the event as follows:

    private void CalculateOrder()
    {
        double partsTotal = 0.00D;
        double taxRate = 0.00D;
        double taxAmount, orderTotal;
    
        if (string.IsNullOrEmpty(txtTaxRate.Text))
            txtTaxRate.Text = "7.25";
    
        foreach (ListViewItem lvi in lvwSelectedParts.Items)
        {
            ListViewItem.ListViewSubItem SubItem = lvi.SubItems[4];
            partsTotal += double.Parse(SubItem.Text);
        }
    
        try
        {
            taxRate = double.Parse(txtTaxRate.Text) / 100;
        }
        catch (FormatException)
        {
            MsgBox.Regular("Invalid Tax Rate");
        }
    
        taxAmount = partsTotal * taxRate;
        orderTotal = partsTotal + taxAmount;
    
        txtSelectedPartsTotal.Text = partsTotal.ToString("F");
        txtTaxAmount.Text = taxAmount.ToString("F");
        txtOrderTotal.Text = orderTotal.ToString("F");
    }
    
    void btnAdd_Click(object sender, EventArgs e)
    {
        if (string.IsNullOrEmpty(txtPartNumber.Text))
        {
            MsgBox.Regular("There is no part to be added to the order.");
            return;
        }
    
        foreach (AutoPart part in AutoParts)
        {
            if (part.PartNumber == long.Parse(txtPartNumber.Text))
            {
                ListViewItem lviSelectedPart = new ListViewItem(part.PartNumber.ToString());
    
                lviSelectedPart.SubItems.Add(part.PartName);
                lviSelectedPart.SubItems.Add(part.UnitPrice.ToString());
                lviSelectedPart.SubItems.Add(txtQuantity.Text);
                lviSelectedPart.SubItems.Add(txtSubTotal.Text);
                lvwSelectedParts.Items.Add(lviSelectedPart);
            }
        }
    
        CalculateOrder();
    }

30. Return to the Store Inventory form and click the Selected Parts list view
31. In the Events section of the Properties window, double-click DoubleClick
32. Implement the event as follows:

    private void lvwSelectedParts_DoubleClick(object sender, EventArgs e)
    {
        ListViewItem lviSelectedPart = lvwSelectedParts.SelectedItems[0];
    
        if ((lvwSelectedParts.SelectedItems.Count == 0) ||
            (lvwSelectedParts.SelectedItems.Count > 1))
            return;
    
        txtPartNumber.Text = lviSelectedPart.Text;
        txtPartName.Text = lviSelectedPart.SubItems[1].Text;
        txtUnitPrice.Text = lviSelectedPart.SubItems[2].Text;
        txtQuantity.Text = lviSelectedPart.SubItems[3].Text;
        txtSubTotal.Text = lviSelectedPart.SubItems[4].Text;
    
        lvwSelectedParts.Items.Remove(lviSelectedPart);
        CalculateOrder();
    }

33. Return to the Store Inventory form and click the Part Identification tree view
34. In the Events section of the Properties window, double-click NodeMouseClick
35. Implement the event as follows:

    private void tvwAutoParts_NodeMouseClick(object sender, TreeNodeMouseClickEventArgs e)
    {
        TreeNode nodClicked = e.Node!;
    
        if (nodClicked.Level == 4)
            lvwAvailableParts.Items.Clear();
    
        try
        {
            foreach (AutoPart part in AutoParts)
            {
                if ((part.Category == nodClicked.Text) &&
                    (part.Model == nodClicked.Parent!.Text) &&
                    (part.Make == nodClicked.Parent.Parent!.Text) &&
                    (part.Year.ToString() == nodClicked.Parent.Parent.Parent!.Text))
                {
                    ListViewItem lviAutoPart = new ListViewItem(part.PartNumber.ToString());
    
                    lviAutoPart.SubItems.Add(part.PartName);
                    lviAutoPart.SubItems.Add(part.UnitPrice.ToString("F"));
                    lvwAvailableParts.Items.Add(lviAutoPart);
                }
            }
        }
        catch (NullReferenceException)
        {
        }
    }

36. Return to the Store Inventory form and double-click the New Auto Part button
37. Implement the event as follows:

    private void btnNewAutoPart_Click(object sender, EventArgs e)
    {
        StoreItemNew nsi = new StoreItemNew();
    
        nsi.ShowDialog();
    
        InitializeAutoParts();
    }

38. To execute the application, on the main menu, click Debug and click Start Without Debugging

    

39. Click the New Auto Part button and create some auto-parts records with the following values:

    

    Part #	Year	Make	Model	Category	Item Name	Unit Price	Picture File
    393795	2015	Buick	Regal	Alternators & Generators	DB Electrical Alternator	218.74	928037
    155975	2010	Buick	Lacrosse	Hub Assemblies	Front/Rear Wheel Hub Bearing Assembly	94.98	155975
    928374	2018	Chevrolet	Express 3500	Shocks, Struts & Suspension	Suspension Kit (Front; with 3 Groove Pitman Arm)	142.44	304031
    730283	2020	Jeep	Wrangler Unlimited Sahara	Oil Filters	Hydraulic Cylinder Timing Belt Tensioner	14.15	730283
    290741	2015	Ford	F-150 XL 3.5L V6 Flex Regular Cab 2 Full-Size Doors	Shocks, Struts & Suspension	Front Strut and Coil Spring Assembly - Set of 2	245.68	290741
    740248	2013	Chevrolet	Equinox	Bearings & Seals	Wheel hub bearing Assembly	99.95	740248
    283759	2012	Dodge	Charger 3.6L	Starters	DB Electrical SND0787 Starter	212.58	283759
    799428	2012	Cadillac	XTS	Bearings & Seals	Front/Rear Wheel Hub Bearing Assembly 5 Lugs w/ABS	79.97	799428
    648203	2018	Honda	CRV	Alternator	Alternator	202.47	593804
    502853	2014	GMC	Terrain	Bearings & Seals	Wheel Hub Bearing Assembly	48.85	927944
    520384	2020	Jeep	Wrangler Unlimited Sahara	Drum Brake	Rear Dynamic Friction Company True-Arc Brake Shoes	42.22	520384
    727394	2018	Toyota	Corolla SE 1.8L L4 Gas	Alternators	DB Electrical 400-40169 Alternator Compatible With/Replacement For 125 Internal Fan Type Decoupler Pulley Type Internal Regulator CW Rotation	215.84	727394
    927944	2017	Chevrolet	Equinox	Bearings & Seals	Wheel Hub Bearing Assembly	48.85	927944
    749471	2019	Toyota	Prius	Shocks, Struts & Suspension	2-Piece Suspension Strut and Coil Spring Kit (593024)	299.97	593024
    927307	2014	Buick	Regal	Alternators & Generators	DB Electrical Alternator	218.74	928037
    304031	2017	Chevrolet	Express 2500	Shocks, Struts & Suspension	Suspension Kit (Front; with 3 Groove Pitman Arm)	142.44	304031
    497249	2013	GMC	Sierra 1500	Drum Brake	ACDelco Gold 17960BF1 Bonded Rear Drum Brake Shoe Set	58.92	497249
    973947	2012	Honda	Accord	Brake Kits	R1 Concepts Front Rear Brakes and Rotors Kit |Front Rear Brake Pads| Brake Rotors and Pads| Ceramic Brake Pads and Rotors	292.84	973947
    182694	2016	Chevrolet	Impala	Bearings & Seals	Wheel Hub Bearing Assembly	48.85	927944
    497249	2013	Chevrolet	Silverado 1500	Drum Brake	ACDelco Gold 17960BF1 Bonded Rear Drum Brake Shoe Set	58.92	497249
    297149	2020	Jeep	Wrangler	Air Filters	ACDelco Gold A3408C Air Filter	22.83	297149
    927397	2016	Chevrolet	Impala	Bearings & Seals	Front/Rear Wheel Hub Bearing Assembly 5 Lugs w/ABS	79.97	799428
    392972	2020	Toyota	Prius AWD-e	Shocks, Struts & Suspension	2-Piece Suspension Strut and Coil Spring Kit (593024)	299.97	593024
    928037	2017	Buick	Regal	Alternators & Generators	DB Electrical Alternator	218.74	928037
    502481	2016	Chevrolet	Equinox	Bearings & Seals	Wheel hub bearing Assembly	99.95	740248
    593804	2019	Honda	Accord LX 1.5L L4 Gas	Alternator	Alternator	202.47	593804
    293748	2014	Toyota	Corolla SE 1.8L L4 Gas	Alternators	DB Electrical 400-40169 Alternator Compatible With/Replacement For 125 Internal Fan Type Decoupler Pulley Type Internal Regulator CW Rotation	215.84	727394
    639704	2021	Kia	Sorento	Brake Kits	Rear Brakes and Rotors Kit |Rear Brake Pads| Brake Rotors and Pads| Optimum OEp Brake Pads and Rotors	125.15	639704
    829385	2020	Jeep	Wrangler Unlimited Sahara	Drum Brake	Centric Brake Shoe	22.05	829385
    484695	2014	GMC	Terrain	Bearings & Seals	Front/Rear Wheel Hub Bearing Assembly 5 Lugs w/ABS	79.97	799428
    807204	2016	Chevrolet	Camaro	Alternators & Generators	DB Electrical Alternator	218.74	928037
    939283	2015	Chevrolet	Equinox	Bearings & Seals	Wheel Hub Bearing Assembly	48.85	927944
    738628	2021	Toyota	Prius AWD-e	Shocks, Struts & Suspension	2-Piece Suspension Strut and Coil Spring Kit (593024)	299.97	593024
    186950	2017	Honda	CRV	Alternator	Alternator	202.47	593804
    329573	2012	Chevrolet	Equinox	Bearings & Seals	Front/Rear Wheel Hub Bearing Assembly 5 Lugs w/ABS	79.97	799428
    594085	2015	Buick	Regal	Bearings & Seals	Front/Rear Wheel Hub Bearing Assembly 5 Lugs w/ABS	79.97	799428
    928405	2018	Chevrolet	Camaro	Alternators & Generators	DB Electrical Alternator	218.74	928037
    927937	2012	Ford	Focus SE	Starters	Duralast Starter 19481	188.88	927937
    283948	2018	GMC	Savana 3500	Shocks, Struts & Suspension	Suspension Kit (Front; with 3 Groove Pitman Arm)	142.44	304031
    495116	2020	Chrysler	Voyager	Brake Kits	Power Stop K7845 Rear Z23 Carbon Fiber Brake Pads with Drilled & Slotted Brake Rotors Kit	269.75	293748
    180400	2012	Cadillac	CTS FWD	Bearings & Seals	Front/Rear Wheel Hub Bearing Assembly 5 Lugs w/ABS	79.97	799428
    593024	2021	Toyota	Prius	Shocks, Struts & Suspension	2-Piece Suspension Strut and Coil Spring Kit (593024)	299.97	593024
    302839	2014	Chevrolet	Equinox	Bearings & Seals	Wheel Hub Bearing Assembly	48.85	927944
    649394	2020	Jeep	Wrangler Unlimited Sahara	Brake Kits	Power Stop K7940 Front Z23 Evolution Sport Brake Upgrade Kit	354.46	495116
    820684	2015	Buick	LaCrosse	Bearings & Seals	Front/Rear Wheel Hub Bearing Assembly 5 Lugs w/ABS	79.97	799428

40. Close the forms and return to your programming environment

Store Item Details

In our application, we will provide a form that an employee can use to view the information related to a certain auto part.

Practical Learning: Getting the Details of an Auto Part

1. To create a new form, on the main menu, click Project -> Add Form (Windows Forms)...
2. Set the name to StoreItemDetails
3. Click Add
4. Click an unoccupied area of the form and, in the Properties window, change the following characteristics:
   Text: College Park Auto-Parts - Store Item Details
   MaximizeBox: False
   StartPosition: CenterScreen
5. Design the form as follows:

   

   Control		(Name)	Text	Other Properties
   Label			&Part #:
   Text Box		txtPartNumber
   Button		btnFindAutoPart	&Find Auto-Part
   Label		lblPictureFile	Generic
   Label			&Year:
   Text Box		txtYear
   Picture Box		pbxPartImage		BorderStyle: FixedSingle: SizeMode: AutoSize
   Label			&Make:
   Text Box		txtMake
   Label			M&odel:
   Text Box		txtModel
   Label			Ca&tegory:
   Text Box		txtCategory
   Label			Part Na&me:
   Text Box		txtPartName		ScrollBars: Vertical Multiline: True
   Label			&Unit Price
   Text Box		txtUnitPrice
   Label			____________________
   Button		btnClose	&Close

6. Double-click the Find Store Item button
7. Define the event as follows:

   using CollegeParkAutoParts1.Models;
   using System.Xml.Serialization;
   
   namespace CollegeParkAutoParts1
   {
       public partial class StoreItemDetails : Form
       {
           List<AutoPart> AutoParts { get; set; } = new List<AutoPart>();
   
           public StoreItemDetails()
           {
               InitializeComponent();
           }
   
           private void btnFindStoreItem_Click(object sender, EventArgs e)
           {
               if (string.IsNullOrEmpty(txtPartNumber.Text))
               {
                   MsgBox.Regular("You must enter a (valid) number for an auto-part.");
                   return;
               }
   
               bool foundAutoPart = false;
               string strFileName = @"C:\College Park Auto-Parts10\AutoParts.xml";
               XmlSerializer xsAutoParts = new XmlSerializer(typeof(List<AutoPart>));
   
               if (File.Exists(strFileName))
               {
                   using (FileStream fsAutoParts = new(strFileName, FileMode.Open, FileAccess.Read, FileShare.Read))
                   {
                       AutoParts = (List<AutoPart>)xsAutoParts.Deserialize(fsAutoParts)!;
   
                       for (int i = 0; i < AutoParts.Count; i++)
                       {
                           if (AutoParts[i].PartNumber.Equals(long.Parse(txtPartNumber.Text)))
                           {
                               foundAutoPart = true;
   
                               txtMake.Text = AutoParts[i].Make;
                               txtModel.Text = AutoParts[i].Model;
                               txtCategory.Text = AutoParts[i].Category;
                               txtPartName.Text = AutoParts[i].PartName;
                               txtYear.Text = AutoParts[i].Year.ToString();
                               txtUnitPrice.Text = AutoParts[i].UnitPrice.ToString("F");
                               pbxPartImage.Image = Image.FromFile(AutoParts[i].PictureFile!);
                               lblPictureFile.Text = AutoParts[i].PictureFile;
   
                               break;
                           }
                       }
                   }
               }
   
               if (foundAutoPart == false)
               {
                   MsgBox.Regular("There is no auto-part with that number in our records.");
   
                   lblPictureFile.Text = @"C:\College Park Auto-Parts10\Generic.png";
                   pbxPartImage.Image = Image.FromFile(@"C:\College Park Auto-Parts10\Generic.png");
               }
   
               Width = pbxPartImage.Right + 40;
               Height = pbxPartImage.Bottom + 75;
           }
       }
   }

8. Return to the Store Item Editor form and double-click the Close button
9. Define the event as follows:

   using CollegeParkAutoParts1.Models;
   using System.Xml.Serialization;
   
   namespace CollegeParkAutoParts1
   {
       public partial class StoreItemDetails : Form
       {
           /* The list of auto-parts of our database will be retrieved using a collection class.
            * This property will hold the list of auto-parts. */
           List<AutoPart> AutoParts { get; set; } = new List<AutoPart>();
   
           public StoreItemDetails()
           {
               InitializeComponent();
           }
   
           private void btnFindStoreItem_Click(object sender, EventArgs e)
           {
               /* When the user clicks the Find Store Item button, make sure the user typed something.
                * If the Part # text box is empty (meaning the user didn't type a number), ...*/
               if (string.IsNullOrEmpty(txtPartNumber.Text))
               {
                   // ... display a message box to the user, ...
                   MsgBox.Regular("You must enter a (valid) number for an auto-part.");
                   // ... and stop everything
                   return;
               }
   
               // This Boolean variable will allow us to know if an auto part was found.
               bool foundAutoPart = false;
               /* Our list of auto-parts is stored in an XML file.
                * Let's get a reference to that file. */
               string strFileName = @"C:\College Park Auto-Parts10\AutoParts.xml";
               /* We process our records through XML serialization.
                * Create a reference for XML serialization that is initialized with a collection class*/
               XmlSerializer xsAutoParts = new XmlSerializer(typeof(List<AutoPart>));
   
               // Before doing anything, check whether a file of auto-parts exists
               if (File.Exists(strFileName))
               {
                   // Create a stream reference for our file of au-parts
                   using (FileStream fsAutoParts = new(strFileName, FileMode.Open, FileAccess.Read, FileShare.Read))
                   {
                       /* If the file of auto-parts exists, open that file, get the list of 
                        * auto-parts, and store that list in our collection variable. */
                       AutoParts = (List<AutoPart>)xsAutoParts.Deserialize(fsAutoParts)!;
   
                       // Now that the list of auto-parts exists, navigate to each item of the list
                       for (int i = 0; i < AutoParts.Count; i++)
                       {
                           /* When you reach an auto-part, check whether its part number is 
                            * the same as the number the user typed.*/
                           if (AutoParts[i].PartNumber.Equals(long.Parse(txtPartNumber.Text)))
                           {
                               // If the auto-part was found, make a not by updating our Boolean variable
                               foundAutoPart = true;
   
                               // Get the values of the auto-part and display them in the Windows controls
                               txtMake.Text = AutoParts[i].Make;
                               txtModel.Text = AutoParts[i].Model;
                               txtCategory.Text = AutoParts[i].Category;
                               txtPartName.Text = AutoParts[i].PartName;
                               txtYear.Text = AutoParts[i].Year.ToString();
                               txtUnitPrice.Text = AutoParts[i].UnitPrice.ToString("F");
                               pbxPartImage.Image = Image.FromFile(AutoParts[i].PictureFile!);
                               lblPictureFile.Text = AutoParts[i].PictureFile;
                               /* Since an auto-part was found 
                                * and its values have been displayed, stop searching. */
                               break;
                           }
                       }
                   }
               }
   
               // Check the value of our Boolean variable. If that value is false, ...
               if (foundAutoPart == false)
               {
                   // ... it means no auto-part was found. Display a message box to the user
                   MsgBox.Regular("There is no auto-part with that number in our records.");
   
                   lblPictureFile.Text = @"C:\College Park Auto-Parts10\Generic.png";
                   pbxPartImage.Image = Image.FromFile(@"C:\College Park Auto-Parts10\Generic.png");
               }
   
               Width = pbxPartImage.Right + 40;
               Height = pbxPartImage.Bottom + 75;
           }
   
           private void btnClose_Click(object sender, EventArgs e)
           {
               Close();
           }
       }
   }

10. Display the Store Inventory form
11. Add an Auto Part Details button as follows:

    

    Control		(Name)	Text
    Button		btnAutoPartDetails	Auto Part &Details...

12. Double-click the Auto Part Details button
13. Implement the event as follows:

    private void btnAutoPartDetails_Click(object sender, EventArgs e)
    {
        StoreItemDetails details = new StoreItemDetails();
    
        details.Show();
    }

14. To execute, on the main menu, click Debug and click Start Without Debugging:

    

15. Click the Auto Part Details button:

    

16. In the Part # text box, type 155975
17. Click the Find Store Item button:

    

18. Close the forms and return to your programming environment

Store Item EdItor

Updating a record consists of changing one or more of its details. To support this operation in our application, we will create an appropriate form.

Practical Learning: Creating a Store Item Editor

1. To create a new form, on the main menu, click Project -> Add Form (Windows Forms)...
2. Set the name to StoreItemEditor
3. Click Add
4. Click an unoccupied area of the form and, in the Properties window, change the following characteristics:
   Text: College Park Auto-Parts - Store Item Editor
   MaximizeBox: False
   StartPosition: CenterScreen
5. Resize the form to have the same size as the New Store Item form
6. Select and copy all controls from the Store Item New form
7. Paste the copied controls on the Store Item Editor form
8. Modify the design of the Store Item Editor form as follows:
    

   

   Control		(Name)	Text
   Button		btnFindStoreItem	&Find Store Item
   Button		btnUpdateAutoPart	Up&date Auto-Part

9. Double-click an unoccupied area of the form
10. Change the document as follows:

    using CollegeParkAutoParts1.Models;
    using System.Xml.Serialization;
    
    namespace CollegeParkAutoParts1
    {
        public partial class StoreItemEditor : Form
        {
            List<AutoPart> AutoParts { get; set; } = new List<AutoPart>();
    
            public StoreItemEditor()
            {
                InitializeComponent();
            }
    
            private void InitializeAutoPart()
            {
                string strFileName = @"C:\College Park Auto-Parts10\AutoParts.xml";
                XmlSerializer xsAutoParts = new XmlSerializer(typeof(List<AutoPart>));
    
                cbxYears.Items.Clear();
    
                for (int year = DateTime.Today.Year + 1; year >= DateTime.Today.Year - 20; year--)
                {
                    cbxYears.Items.Add(year);
                }
    
                if (File.Exists(strFileName))
                {
                    cbxMakes.Items.Clear();
                    cbxModels.Items.Clear();
                    cbxCategories.Items.Clear();
                    txtPartName.Text = string.Empty;
                    txtUnitPrice.Text = string.Empty;
                    txtPartNumber.Text = string.Empty;
    
                    using (FileStream fsAutoParts = new FileStream(strFileName,
                                                                   FileMode.Open,
                                                                   FileAccess.Read,
                                                                   FileShare.Read))
                    {
                        AutoParts = (List<AutoPart>)xsAutoParts.Deserialize(fsAutoParts)!;
    
                        for (int i = 0; i < AutoParts.Count; i++)
                        {
                            if (!cbxMakes.Items.Contains(AutoParts[i].Make))
                            {
                                cbxMakes.Items.Add(AutoParts[i].Make!);
                            }
                        }
    
                        for (int i = 0; i < AutoParts.Count; i++)
                        {
                            if (!cbxCategories.Items.Contains(AutoParts[i].Category))
                            {
                                cbxCategories.Items.Add(AutoParts[i].Category!);
                            }
                        }
                    }
                }
    
                lblPictureFile.Text = @"C:\College Park Auto-Parts10\Generic.png";
                pbxPartImage.Image = Image.FromFile(@"C:\College Park Auto-Parts10\Generic.png");
    
                Width = pbxPartImage.Right + 40;
                Height = pbxPartImage.Bottom + 75;
            }
    
            private void StoreItemEditor_Load(object sender, EventArgs e)
            {
                InitializeAutoPart();
            }
        }
    }

11. Return to the Store Item Editor form and double-click the Find Store Item button
12. Implement the event as follows:

    private void btnFindStoreItem_Click(object sender, EventArgs e)
    {
        if (string.IsNullOrEmpty(txtPartNumber.Text))
        {
            MsgBox.Regular("You must enter a (valid) number for an auto-part.");
            return;
        }
    
        bool foundAutoPart = false;
        string strFileName = @"C:\College Park Auto-Parts10\AutoParts.xml";
        XmlSerializer xsAutoParts = new XmlSerializer(typeof(List<AutoPart>));
    
        if (File.Exists(strFileName))
        {
            using (FileStream fsAutoParts = new(strFileName, FileMode.Open, FileAccess.Read, FileShare.Read))
            {
                AutoParts = (List<AutoPart>)xsAutoParts.Deserialize(fsAutoParts)!;
    
                for (int i = 0; i < AutoParts.Count; i++)
                {
                    if (AutoParts[i].PartNumber.Equals(long.Parse(txtPartNumber.Text)))
                    {
                        foundAutoPart = true;
    
                        cbxMakes.Text = AutoParts[i].Make;
                        cbxModels.Text = AutoParts[i].Model;
                        cbxCategories.Text = AutoParts[i].Category;
                        txtPartName.Text = AutoParts[i].PartName;
                        cbxYears.Text = AutoParts[i].Year.ToString();
                        txtUnitPrice.Text = AutoParts[i].UnitPrice.ToString("F");
                        pbxPartImage.Image = Image.FromFile(AutoParts[i].PictureFile!);
                        lblPictureFile.Text = AutoParts[i].PictureFile;
    
                        break;
                    }
                }
            }
        }
    
        if (foundAutoPart == false)
        {
            MsgBox.Regular("There is no auto-part with that number in our records.");
    
            lblPictureFile.Text = @"C:\College Park Auto-Parts\Generic.png";
            pbxPartImage.Image = Image.FromFile(@"C:\College Park Auto-Parts\Generic.png");
        }
    
        Width = pbxPartImage.Right + 40;
        Height = pbxPartImage.Bottom + 75;
    }

13. Return to the Store Item Editor form and double-click the Select Picture button
14. Implement the event as follows:

    private void btnSelectPicture_Click(object sender, EventArgs e)
    {
        if (ofdPictureFile.ShowDialog() == DialogResult.OK)
        {
            lblPictureFile.Text = ofdPictureFile.FileName;
            pbxPartImage.Image = Image.FromFile(ofdPictureFile.FileName);
        }
        else
        {
            pbxPartImage.Image = Image.FromFile(@"C:\College Park Auto-Parts10\Generic.png");
        }
    
        Width = pbxPartImage.Right + 40;
        Height = pbxPartImage.Bottom + 75;
    }

15. Return to the form and double-click the Makes combo box to generate its Selected Index event
16. Implement the event as follows:

    private void cbxMakes_SelectedIndexChanged(object sender, EventArgs e)
    {
        cbxModels.Items.Clear();
        cbxModels.Text = string.Empty;
    
        foreach (AutoPart part in AutoParts)
        {
            if (part.Make == cbxMakes.Text)
            {
                if (!cbxModels.Items.Contains(part.Model))
                {
                    cbxModels.Items.Add(part.Model!);
                }
            }
        }
    }

17. Return to the form and double-click the New Make button
18. Implement the event as follows:

    private void btnNewMake_Click(object sender, EventArgs e)
    {
        Make editor = new Make();
    
        if (editor.ShowDialog() == DialogResult.OK)
        {
            if (editor.txtMake.Text.Length > 0)
            {
                string strMake = editor.txtMake.Text;
    
                if (cbxMakes.Items.Contains(strMake))
                {
                    MsgBox.Regular(strMake + " is already in the list.");
                }
                else
                {
                    cbxMakes.Items.Add(strMake);
                }
    
                cbxMakes.Text = strMake;
            }
        }
    }

19. Return to the form and double-click the New Model button
20. Implement the event as follows:

    private void btnNewModel_Click(object sender, EventArgs e)
    {
        Model editor = new();
    
        if (editor.ShowDialog() == DialogResult.OK)
        {
            if (editor.txtModel.Text.Length > 0)
            {
                string strModel = editor.txtModel.Text;
    
                if (cbxModels.Items.Contains(strModel))
                {
                    MsgBox.Regular(strModel + " is already in the list.");
                }
                else
                {
                    cbxModels.Items.Add(strModel);
                }
    
                cbxModels.Text = strModel;
            }
        }
    }

21. Return to the form and double-click the New Category button
22. Implement the event as follows:

    private void btnNewCategory_Click(object sender, EventArgs e)
    {
        var editor = new Category();
    
        if (editor.ShowDialog() == DialogResult.OK)
        {
            if (editor.txtCategory.Text.Length > 0)
            {
                string strCategory = editor.txtCategory.Text;
    
                if (cbxCategories.Items.Contains(strCategory))
                {
                    MsgBox.Regular(strCategory + " is already in the list.");
                }
                else
                {
                    cbxCategories.Items.Add(strCategory);
                }
    
                cbxCategories.Text = strCategory;
            }
        }
    }

23. Return to the Store Item Editor form and double-click the Update Auto-Part button
24. Implement the event as follows:

    private void btnUpdateAutoPart_Click(object sender, EventArgs e)
    {
        string strFileName = @"C:\College Park Auto-Parts10\AutoParts.xml";
        XmlSerializer xsAutoParts = new XmlSerializer(typeof(List<AutoPart>));
    
        if (File.Exists(strFileName))
        {
            using (FileStream fsAutoParts = new FileStream(strFileName,
                                                            FileMode.Open,
                                                            FileAccess.Read,
                                                            FileShare.Read))
            {
                AutoParts = (List<AutoPart>)xsAutoParts.Deserialize(fsAutoParts)!;
            }
        }
    
        for (int i = 0; i < AutoParts.Count; i++)
        {
            if (AutoParts[i].PartNumber.Equals(long.Parse(txtPartNumber.Text)))
            {
                AutoParts[i].Year = Convert.ToInt32(cbxYears.Text);
                AutoParts[i].Make = cbxMakes.Text;
                AutoParts[i].Model = cbxModels.Text;
                AutoParts[i].Category = cbxCategories.Text;
                AutoParts[i].PartName = txtPartName.Text;
                AutoParts[i].UnitPrice = Convert.ToDouble(txtUnitPrice.Text);
                AutoParts[i].PictureFile = lblPictureFile.Text;
    
                TextWriter twAutoParts = new StreamWriter(strFileName);
                xsAutoParts.Serialize(twAutoParts, AutoParts);
                twAutoParts.Close();
    
                break;
            }
        }
    
        InitializeAutoPart();
    }

25. Return to the Store Item Editor form and double-click the Close button
26. Change the document as follows:

    using CollegeParkAutoParts1.Models;
    using System.Xml.Serialization;
    
    namespace CollegeParkAutoParts1
    {
        public partial class StoreItemEditor : Form
        {
            /* This property is used to hold the list of auto-parts of our application.
             * (We didn't have to use a global variable. We could have used local variables.) */
            List<AutoPart> AutoParts { get; set; } = new List<AutoPart>();
    
            public StoreItemEditor()
            {
                InitializeComponent();
            }
    
            /* This function is used to reset the form.
             * It can be called when necessary. */
            private void InitializeAutoPart()
            {
                // This file is the repository of our database
                string strFileName = @"C:\College Park Auto-Parts10\AutoParts.xml";
                // We will use XML serialization to manage the records of our database
                XmlSerializer xsAutoParts = new XmlSerializer(typeof(List<AutoPart>));
    
                cbxYears.Items.Clear();
    
                /* Show the years in the top combo box.
                 * We will consider only the cars made in the last 20 years. */
                for (int year = DateTime.Today.Year + 1; year >= DateTime.Today.Year - 20; year--)
                {
                    cbxYears.Items.Add(year);
                }
    
                // Check whether the file that holds the store inventory was created already
                if (File.Exists(strFileName))
                {
                    cbxMakes.Items.Clear();
                    cbxModels.Items.Clear();
                    cbxCategories.Items.Clear();
                    txtPartName.Text = string.Empty;
                    txtUnitPrice.Text = string.Empty;
                    txtPartNumber.Text = string.Empty;
    
                    // If the inventory file exists, open it
                    using (FileStream fsAutoParts = new FileStream(strFileName,
                                                                   FileMode.Open,
                                                                   FileAccess.Read,
                                                                   FileShare.Read))
                    {
                        // Retrieve the list of items from file
                        AutoParts = (List<AutoPart>)xsAutoParts.Deserialize(fsAutoParts)!;
    
                        // Display the cars manufacturers in the combo box
                        for (int i = 0; i < AutoParts.Count; i++)
                        {
                            // Make sure the list box doesn't yet have the category being added
                            if (!cbxMakes.Items.Contains(AutoParts[i].Make))
                            {
                                cbxMakes.Items.Add(AutoParts[i].Make!);
                            }
                        }
    
                        // Display the categories in the box
                        for (int i = 0; i < AutoParts.Count; i++)
                        {
                            // Make sure the list box doesn't yet have the category being added
                            if (!cbxCategories.Items.Contains(AutoParts[i].Category))
                            {
                                cbxCategories.Items.Add(AutoParts[i].Category!);
                            }
                        }
                    }
                }
    
                // Display the path of the default picture file of the auto part in the top-right label
                lblPictureFile.Text = @"C:\College Park Auto-Parts10\Generic.png";
                // Display the default auto-part image in the picture box
                pbxPartImage.Image = Image.FromFile(@"C:\College Park Auto-Parts10\Generic.png");
    
                // Resize the form to show the whole auto-part image
                Width = pbxPartImage.Right + 40;
                Height = pbxPartImage.Bottom + 75;
            }
    
            private void StoreItemEditor_Load(object sender, EventArgs e)
            {
                InitializeAutoPart();
            }
    
            private void btnFindStoreItem_Click(object sender, EventArgs e)
            {
                /* When the user clicks the Find Store Item button, make sure the user typed something.
                 * If the Part # text box is empty (meaning the user didn't type a number), ...*/
                if (string.IsNullOrEmpty(txtPartNumber.Text))
                {
                    // ... display a message box to the user, ...
                    MsgBox.Regular("You must enter a (valid) number for an auto-part.");
                    // ... and stop everything
                    return;
                }
    
                // This Boolean variable will allow us to know if an auto part was found.
                bool foundAutoPart = false;
                /* Our list of auto-parts is stored in an XML file.
                 * Let's get a reference to that file. */
                string strFileName = @"C:\College Park Auto-Parts10\AutoParts.xml";
                /* We process our records through XML serialization.
                 * Create a reference for XML serialization that is initialized with a collection class*/
                XmlSerializer xsAutoParts = new XmlSerializer(typeof(List<AutoPart>));
    
                // Before doing anything, check whether a file of auto-parts exists
                if (File.Exists(strFileName))
                {
                    // Create a stream reference for our file of au-parts
                    using (FileStream fsAutoParts = new(strFileName, FileMode.Open, FileAccess.Read, FileShare.Read))
                    {
                        /* If the file of auto-parts exists, open that file, get the list of 
                         * auto-parts, and store that list in our collection variable. */
                        AutoParts = (List<AutoPart>)xsAutoParts.Deserialize(fsAutoParts)!;
    
                        // Now that the list of auto-parts exists, navigate to each item of the list
                        for (int i = 0; i < AutoParts.Count; i++)
                        {
                            /* When you reach an auto-part, check whether its part number is 
                             * the same as the number the user typed.*/
                            if (AutoParts[i].PartNumber.Equals(long.Parse(txtPartNumber.Text)))
                            {
                                // If the auto-part was found, make a not by updating our Boolean variable
                                foundAutoPart = true;
    
                                cbxMakes.Text = AutoParts[i].Make;
                                cbxModels.Text = AutoParts[i].Model;
                                cbxCategories.Text = AutoParts[i].Category;
                                txtPartName.Text = AutoParts[i].PartName;
                                cbxYears.Text = AutoParts[i].Year.ToString();
                                txtUnitPrice.Text = AutoParts[i].UnitPrice.ToString("F");
                                pbxPartImage.Image = Image.FromFile(AutoParts[i].PictureFile!);
                                lblPictureFile.Text = AutoParts[i].PictureFile;
                                /* Since an auto-part was found 
                                 * and its values have been displayed, stop searching. */
                                break;
                            }
                        }
                    }
                }
    
                // Check the value of our Boolean variable. If that value is false, ...
                if (foundAutoPart == false)
                {
                    // ... it means no auto-part was found. Display a message box to the user
                    MsgBox.Regular("There is no auto-part with that number in our records.");
    
                    lblPictureFile.Text = @"C:\College Park Auto-Parts\Generic.png";
                    pbxPartImage.Image = Image.FromFile(@"C:\College Park Auto-Parts\Generic.png");
                }
    
                Width = pbxPartImage.Right + 40;
                Height = pbxPartImage.Bottom + 75;
            }
    
            private void btnSelectPicture_Click(object sender, EventArgs e)
            {
                // When the user clicks the Select Picture button, display the Open File Dialog box
                if (ofdPictureFile.ShowDialog() == DialogResult.OK)
                {
                    /* If the user selects a picture and clicks OK, ...
                     * display the path of the picture file in the top-right label, ...*/
                    lblPictureFile.Text = ofdPictureFile.FileName;
                    // ... display the auto picture in the picture box
                    pbxPartImage.Image = Image.FromFile(ofdPictureFile.FileName);
                }
                else
                {
                    // If the user didn't select a valid picture, display the default one
                    pbxPartImage.Image = Image.FromFile(@"C:\College Park Auto-Parts10\Generic.png");
                }
    
                // Resize the form to show the whole auto-part image
                Width = pbxPartImage.Right + 40;
                Height = pbxPartImage.Bottom + 75;
            }
    
            private void cbxMakes_SelectedIndexChanged(object sender, EventArgs e)
            {
                cbxModels.Items.Clear();
                cbxModels.Text = string.Empty;
    
                foreach (AutoPart part in AutoParts)
                {
                    if (part.Make == cbxMakes.Text)
                    {
                        if (!cbxModels.Items.Contains(part.Model))
                        {
                            cbxModels.Items.Add(part.Model!);
                        }
                    }
                }
            }
    
            private void btnNewMake_Click(object sender, EventArgs e)
            {
                Make editor = new Make();
    
                if (editor.ShowDialog() == DialogResult.OK)
                {
                    if (editor.txtMake.Text.Length > 0)
                    {
                        string strMake = editor.txtMake.Text;
    
                        if (cbxMakes.Items.Contains(strMake))
                        {
                            MsgBox.Regular(strMake + " is already in the list.");
                        }
                        else
                        {
                            cbxMakes.Items.Add(strMake);
                        }
    
                        cbxMakes.Text = strMake;
                    }
                }
            }
    
            private void btnNewModel_Click(object sender, EventArgs e)
            {
                Model editor = new();
    
                if (editor.ShowDialog() == DialogResult.OK)
                {
                    if (editor.txtModel.Text.Length > 0)
                    {
                        string strModel = editor.txtModel.Text;
    
                        if (cbxModels.Items.Contains(strModel))
                        {
                            MsgBox.Regular(strModel + " is already in the list.");
                        }
                        else
                        {
                            cbxModels.Items.Add(strModel);
                        }
    
                        cbxModels.Text = strModel;
                    }
                }
            }
    
            private void btnNewCategory_Click(object sender, EventArgs e)
            {
                var editor = new Category();
    
                if (editor.ShowDialog() == DialogResult.OK)
                {
                    if (editor.txtCategory.Text.Length > 0)
                    {
                        string strCategory = editor.txtCategory.Text;
    
                        if (cbxCategories.Items.Contains(strCategory))
                        {
                            MsgBox.Regular(strCategory + " is already in the list.");
                        }
                        else
                        {
                            cbxCategories.Items.Add(strCategory);
                        }
    
                        cbxCategories.Text = strCategory;
                    }
                }
            }
    
            private void btnUpdateAutoPart_Click(object sender, EventArgs e)
            {
                string strFileName = @"C:\College Park Auto-Parts10\AutoParts.xml";
                XmlSerializer xsAutoParts = new XmlSerializer(typeof(List<AutoPart>));
    
                if (File.Exists(strFileName))
                {
                    using (FileStream fsAutoParts = new FileStream(strFileName,
                                                                    FileMode.Open,
                                                                    FileAccess.Read,
                                                                    FileShare.Read))
                    {
                        AutoParts = (List<AutoPart>)xsAutoParts.Deserialize(fsAutoParts)!;
                    }
                }
    
                for (int i = 0; i < AutoParts.Count; i++)
                {
                    if (AutoParts[i].PartNumber.Equals(long.Parse(txtPartNumber.Text)))
                    {
                        AutoParts[i].Year = Convert.ToInt32(cbxYears.Text);
                        AutoParts[i].Make = cbxMakes.Text;
                        AutoParts[i].Model = cbxModels.Text;
                        AutoParts[i].Category = cbxCategories.Text;
                        AutoParts[i].PartName = txtPartName.Text;
                        AutoParts[i].UnitPrice = Convert.ToDouble(txtUnitPrice.Text);
                        AutoParts[i].PictureFile = lblPictureFile.Text;
    
                        TextWriter twAutoParts = new StreamWriter(strFileName);
                        xsAutoParts.Serialize(twAutoParts, AutoParts);
                        twAutoParts.Close();
    
                        break;
                    }
                }
    
                InitializeAutoPart();
            }
    
            private void btnClose_Click(object sender, EventArgs e)
            {
                Close();
            }
        }
    }

27. Display the Store Inventory form
28. Add an Auto Part Editor button as follows:

    

    Control		(Name)	Text
    Button		btnUpdateAutoPart	Update Auto Part...

29. Double-click the Auto Part Details button
30. Implement the event as follows:

    private void btnAutoPartEditor_Click(object sender, EventArgs e)
    {
        StoreItemEditor editor = new StoreItemEditor();
    
        editor.ShowDialog();
    
        InitializeAutoParts();
    }

31. To execute, on the main menu, click Debug and click Start Without Debugging:

    

32. Click the Auto Part Details button:

    

33. In the Part # text box, type 155975
34. Click the Find Store Item button:

    

35. Change the following values:

    Year:       2025
    Model:      Envista
    Part Name:  Multi-Part Front and Rear Wheel Bearing Assembly
    Unit Price: 122.86

36. Close the forms and return to your programming environment

Store Item Deletion

In a typical database application, when an item is not necessary anymore, its records can be removed. To support this operation, we will create an appropriate form.

Practical Learning: Delting a Store Item

1. To add a new form, on the main menu, click Project -> Add Form (Windows Forms)...
2. Type the Name as StoreItemDelete
3. Click Add
4. Click an unoccupied area of the form and, in the Properties window, change the following characteristics:
   Text: College Park Auto-Parts - Store Item Deletion
   MaximizeBox: False
   StartPosition: CenterScreen
5. Resize the Store Item Delete form to have approximately the same size as the Store Item Details form
6. Select and copy all controls on the Store Item Details form
7. Paste the copied controls to the Store Item Delete form
8. Complete the design of the form as follows:

   

   Control		(Name)	Text
   Button		btnDeleteAutoPart	Delete Auto Part...
   Button		btnClose	Close

9. Double-click the Find Store Item button
10. Implement the event as follows:

    using CollegeParkAutoParts1.Models;
    using System.Xml.Serialization;
    
    namespace CollegeParkAutoParts1
    {
        public partial class StoreItemDelete : Form
        {
            List<AutoPart> AutoParts { get; set; } = new List<AutoPart>();
    
            public StoreItemDelete()
            {
                InitializeComponent();
            }
    
            private void btnFindStoreItem_Click(object sender, EventArgs e)
            {
                /* When the user clicks the Find Store Item button, make sure the user typed something.
                 * If the Part # text box is empty (meaning the user didn't type a number), ...*/
                if (string.IsNullOrEmpty(txtPartNumber.Text))
                {
                    // ... display a message box to the user, ...
                    MsgBox.Regular("You must enter a (valid) number for an auto-part.");
                    // ... and stop everything
                    return;
                }
    
                // This Boolean variable will allow us to know if an auto part was found.
                bool foundAutoPart = false;
                /* Our list of auto-parts is stored in an XML file.
                 * Let's get a reference to that file. */
                string strFileName = @"C:\College Park Auto-Parts10\AutoParts.xml";
                /* We process our records through XML serialization.
                 * Create a reference for XML serialization that is initialized with a collection class*/
                XmlSerializer xsAutoParts = new XmlSerializer(typeof(List<AutoPart>));
    
                // Before doing anything, check whether a file of auto-parts exists
                if (File.Exists(strFileName))
                {
                    // Create a stream reference for our file of au-parts
                    using (FileStream fsAutoParts = new(strFileName, FileMode.Open, FileAccess.Read, FileShare.Read))
                    {
                        /* If the file of auto-parts exists, open that file, get the list of 
                         * auto-parts, and store that list in our collection variable. */
                        AutoParts = (List<AutoPart>)xsAutoParts.Deserialize(fsAutoParts)!;
    
                        // Now that the list of auto-parts exists, navigate to each item of the list
                        for (int i = 0; i < AutoParts.Count; i++)
                        {
                            /* When you reach an auto-part, check whether its part number is 
                             * the same as the number the user typed.*/
                            if (AutoParts[i].PartNumber.Equals(long.Parse(txtPartNumber.Text)))
                            {
                                // If the auto-part was found, make a not by updating our Boolean variable
                                foundAutoPart = true;
    
                                // Get the values of the auto-part and display them in the Windows controls
                                txtMake.Text = AutoParts[i].Make;
                                txtModel.Text = AutoParts[i].Model;
                                txtCategory.Text = AutoParts[i].Category;
                                txtPartName.Text = AutoParts[i].PartName;
                                txtYear.Text = AutoParts[i].Year.ToString();
                                txtUnitPrice.Text = AutoParts[i].UnitPrice.ToString("F");
                                pbxPartImage.Image = Image.FromFile(AutoParts[i].PictureFile!);
                                lblPictureFile.Text = AutoParts[i].PictureFile;
                                /* Since an auto-part was found 
                                 * and its values have been displayed, stop searching. */
                                break;
                            }
                        }
                    }
                }
    
                // Check the value of our Boolean variable. If that value is false, ...
                if (foundAutoPart == false)
                {
                    // ... it means no auto-part was found. Display a message box to the user
                    MsgBox.Regular("There is no auto-part with that number in our records.");
    
                    lblPictureFile.Text = @"C:\College Park Auto-Parts10\Generic.png";
                    pbxPartImage.Image = Image.FromFile(@"C:\College Park Auto-Parts10\Generic.png");
                }
    
                Width = pbxPartImage.Right + 40;
                Height = pbxPartImage.Bottom + 75;
            }
        }
    }

11. Return to the form and double-click the Delete Auto Part button
12. Define the event as follows:

    private void btnDeleteAutoPart_Click(object sender, EventArgs e)
    {
        XmlSerializer xsAutoParts = new(typeof(List<AutoPart>));
        string strFileName = @"C:\College Park Auto-Parts10\AutoParts.xml";
    
        if (File.Exists(strFileName))
        {
            using FileStream fsAutoParts = new(strFileName, FileMode.Open,
                                               FileAccess.Read, FileShare.Read);
            AutoParts = (List<AutoPart>)xsAutoParts.Deserialize(fsAutoParts)!;
        }
    
        for (int i = 0; i < AutoParts.Count; i++)
        {
            if (AutoParts[i].PartNumber.Equals(long.Parse(txtPartNumber.Text)))
            {
                AutoParts.Remove(AutoParts[i]);
    
                TextWriter twAutoParts = new StreamWriter(strFileName);
                xsAutoParts.Serialize(twAutoParts, AutoParts);
                twAutoParts.Close();
    
                break;
            }
        }
    
        InitializeAutoPart();
    }

13. Return to the form and double-click the Close button
14. Change the document as follows:

    private void btnClose_Click(object sender, EventArgs e)
    {
        Close();
    }

15. Display the Store Inventory form
16. Add an Auto Part Delete and a Close buttons as follows:

    

    Control		(Name)	Text
    Label		btnDeleteAutoPart	Delete Auto-Part
    Button		btnClose	Close

17. Double-click the Delete Auto-Part button
18. Define the event as follows:

    private void btnDeleteAutoPart_Click(object sender, EventArgs e)
    {
        StoreItemDelete delete = new StoreItemDelete();
    
        delete.ShowDialog();
    
        InitializeAutoParts();
    }

19. Return to the form and double-click the Close button
20. Change the document as follows:

    using CollegeParkAutoParts1.Models;
    using System.Xml.Serialization;
    
    namespace CollegeParkAutoParts1
    {
        public partial class StoreInventory : Form
        {
            /* We will need a list of auto-parts.
             * For demonstration purpose, we are creating the list as a property
             * (but a global list is not necessary; we could have used local list variables).*/
            public List<AutoPart> AutoParts { get; set; } = new List<AutoPart>();
    
            public StoreInventory()
            {
                InitializeComponent();
            }
    
            // This function is used to reset the form
            void InitializeAutoParts()
            {
                // When the form must be reset, removes all nodes from the tree view
                tvwAutoParts.Nodes.Clear();
                // Create the root node of the tree view
                TreeNode nodRoot = tvwAutoParts.Nodes.Add("College Park Auto-Parts",
                                                          "College Park Auto-Parts", 0, 1);
                /* Add the cars years to the tree view.
                 * Our application will deal only with the cars in the last 21 years. */
                for (int years = DateTime.Today.Year + 1; years >= DateTime.Today.Year - 20; years--)
                {
                    nodRoot.Nodes.Add(years.ToString(), years.ToString(), 2, 3);
                }
    
                // Select the root node
                tvwAutoParts.SelectedNode = nodRoot;
                // Expand the root node
                tvwAutoParts.ExpandAll();
    
                // AutoParts = new List<AutoPart>();
    
                // This is the file that holds the list of auto parts
                string strFileName = @"C:\College Park Auto-Parts10\AutoParts.xml";
                // Create an XmlSerializer object to retrieve the list of auto parts from file
                XmlSerializer xsAutoParts = new(typeof(List<AutoPart>));
    
                if (File.Exists(strFileName))
                {
                    // If the inventory file exists, open it
                    using (FileStream fsAutoParts = new FileStream(strFileName,
                                                                    FileMode.Open,
                                                                    FileAccess.Read,
                                                                    FileShare.Read))
                    {
                        // Retrieve the list of items from file
                        AutoParts = (List<AutoPart>)xsAutoParts.Deserialize(fsAutoParts)!;
    
                        // Show the makes nodes
                        foreach (TreeNode nodYear in nodRoot.Nodes)
                        {
                            // Start a new list of car manufacturers
                            List<string> lstMakes = new List<string>();
    
                            // Visit each item from the AutoParts list
                            foreach (AutoPart part in AutoParts)
                            {
                                // When you get to an auto part with the same year as the year of the node, ...
                                if (nodYear.Text == part.Year.ToString())
                                {
                                    // ... add the make to the list of makes
                                    if (!lstMakes.Contains(part.Make!))
                                    {
                                        lstMakes.Add(part.Make!);
                                    }
                                }
                            }
    
                            // For the current year node in the tree view, and from the list of auto-parts, ...
                            foreach (string strMake in lstMakes)
                            {
                                // ... add the make as a node to the tree view
                                nodYear.Nodes.Add(strMake, strMake, 4, 5);
                            }
                        }
    
                        // Show the models that correspond to the makes and years nodes
                        foreach (TreeNode nodYear in nodRoot.Nodes)
                        {
                            foreach (TreeNode nodMake in nodYear.Nodes)
                            {
                                List<string> lstModels = new List<string>();
    
                                foreach (AutoPart part in AutoParts)
                                {
                                    if ((nodYear.Text == part.Year.ToString()) &
                                        (nodMake.Text == part.Make))
                                    {
                                        if (!lstModels.Contains(part.Model!))
                                            lstModels.Add(part.Model!);
                                    }
                                }
    
                                foreach (string strModel in lstModels)
                                    nodMake.Nodes.Add(strModel, strModel, 6, 7);
                            }
                        }
    
                        // Show the categories of items
                        foreach (TreeNode nodYear in nodRoot.Nodes)
                        {
                            foreach (TreeNode nodMake in nodYear.Nodes)
                            {
                                foreach (TreeNode nodModel in nodMake.Nodes)
                                {
                                    List<string> lstCategories = new List<string>();
    
                                    foreach (AutoPart part in AutoParts)
                                    {
    
                                        if ((nodYear.Text == part.Year.ToString()) &
                                            (nodMake.Text == part.Make) &
                                            (nodModel.Text == part.Model))
                                        {
                                            if (!lstCategories.Contains(part.Category!))
                                                lstCategories.Add(part.Category!);
                                        }
                                    }
    
                                    foreach (string strCategory in lstCategories)
                                        nodModel.Nodes.Add(strCategory, strCategory, 8, 9);
                                }
                            }
                        }
                    }
                }
    
                // Reset the form
                lvwSelectedParts.Items.Clear();
                lvwAvailableParts.Items.Clear();
                txtTaxRate.Text = string.Empty;
                txtPartName.Text = string.Empty;
                txtQuantity.Text = string.Empty;
                txtSubTotal.Text = string.Empty;
                txtUnitPrice.Text = string.Empty;
                txtTaxAmount.Text = string.Empty;
                txtOrderTotal.Text = string.Empty;
                txtPartNumber.Text = string.Empty;
                txtSelectedPartsTotal.Text = string.Empty;
                pbxPartImage.Image = Image.FromFile(@"C:\College Park Auto-Parts10\Generic.png");
    
                Width = pbxPartImage.Right + 40;
            }
    
            private void StoreInventory_Load(object sender, EventArgs e)
            {
                InitializeAutoParts();
            }
    
            private void lvwAvailableParts_ItemSelectionChanged(object sender, ListViewItemSelectionChangedEventArgs e)
            {
                bool pictureFound = false;
                string strFileName = @"C:\College Park Auto-Parts10\AutoParts.xml";
                XmlSerializer xsAutoParts = new XmlSerializer(typeof(List<AutoPart>));
    
                if (File.Exists(strFileName))
                {
                    using (FileStream fsAutoParts = new FileStream(strFileName,
                                                                   FileMode.Open,
                                                                   FileAccess.Read,
                                                                   FileShare.Read))
                    {
                        AutoParts = (List<AutoPart>)xsAutoParts.Deserialize(fsAutoParts)!;
    
                        foreach (AutoPart part in AutoParts)
                        {
                            if (part.PartNumber == long.Parse(e.Item!.SubItems[0].Text))
                            {
                                pictureFound = true;
                                pbxPartImage.Image = Image.FromFile(part.PictureFile!);
                                break;
                            }
                        }
                    }
                }
    
                if (pictureFound == false)
                {
                    pbxPartImage.Image = Image.FromFile(@"C:\College Park Auto-Parts10\Generic.png");
                }
    
                Width = pbxPartImage.Right + 40;
                Height = pbxPartImage.Bottom + 75;
            }
    
            private void lvwAvailableParts_DoubleClick(object sender, EventArgs e)
            {
                ListViewItem lviAutoPart = lvwAvailableParts.SelectedItems[0];
    
                if ((lvwAvailableParts.SelectedItems.Count == 0) ||
                    (lvwAvailableParts.SelectedItems.Count > 1))
                    return;
    
                txtPartNumber.Text = lviAutoPart.Text;
                txtPartName.Text = lviAutoPart.SubItems[1].Text;
                txtUnitPrice.Text = lviAutoPart.SubItems[2].Text;
    
                txtQuantity.Text = "1";
                txtSubTotal.Text = lviAutoPart.SubItems[2].Text;
    
                txtQuantity.Focus();
            }
    
            private void txtUnitPrice_Leave(object sender, EventArgs e)
            {
                double subTotal;
                double unitPrice = 0D;
                double quantity = 0.00d;
    
                try
                {
                    unitPrice = double.Parse(txtUnitPrice.Text);
                }
                catch (FormatException)
                {
                    MsgBox.Regular("Invalid Unit Price!");
                }
    
                try
                {
                    quantity = int.Parse(txtQuantity.Text);
                }
                catch (FormatException)
                {
                    MsgBox.Regular("Invalid Quandtity!");
                }
    
                subTotal = unitPrice * quantity;
                txtSubTotal.Text = subTotal.ToString("F");
            }
    
            private void txtPartNumber_Leave(object sender, EventArgs e)
            {
                bool found = false;
    
                foreach (AutoPart part in AutoParts)
                {
                    if (part.PartNumber == long.Parse(txtPartNumber.Text))
                    {
                        txtPartName.Text = part.PartName;
                        txtUnitPrice.Text = part.UnitPrice.ToString("F");
    
                        if (string.IsNullOrEmpty(txtQuantity.Text))
                            txtQuantity.Text = "1";
    
                        txtSubTotal.Text = part.UnitPrice.ToString("F");
    
                        txtQuantity.Focus();
    
                        found = true;
                        break;
                    }
                }
    
                if (found == false)
                {
                    txtPartName.Text = "";
                    txtUnitPrice.Text = "0.00";
                    txtQuantity.Text = "0";
                    txtSubTotal.Text = "0.00";
    
                    MsgBox.Regular("There is no part with that number.");
                }
            }
    
            private void CalculateOrder()
            {
                double partsTotal = 0.00D;
                double taxRate = 0.00D;
                double taxAmount, orderTotal;
    
                if (string.IsNullOrEmpty(txtTaxRate.Text))
                    txtTaxRate.Text = "7.25";
    
                foreach (ListViewItem lvi in lvwSelectedParts.Items)
                {
                    ListViewItem.ListViewSubItem SubItem = lvi.SubItems[4];
                    partsTotal += double.Parse(SubItem.Text);
                }
    
                try
                {
                    taxRate = double.Parse(txtTaxRate.Text) / 100;
                }
                catch (FormatException)
                {
                    MsgBox.Regular("Invalid Tax Rate");
                }
    
                taxAmount = partsTotal * taxRate;
                orderTotal = partsTotal + taxAmount;
    
                txtSelectedPartsTotal.Text = partsTotal.ToString("F");
                txtTaxAmount.Text = taxAmount.ToString("F");
                txtOrderTotal.Text = orderTotal.ToString("F");
            }
    
            private void btnAdd_Click(object sender, EventArgs e)
            {
                if (string.IsNullOrEmpty(txtPartNumber.Text))
                {
                    MsgBox.Regular("There is no part to be added to the order.");
                    return;
                }
    
                foreach (AutoPart part in AutoParts)
                {
                    if (part.PartNumber == long.Parse(txtPartNumber.Text))
                    {
                        ListViewItem lviSelectedPart = new ListViewItem(part.PartNumber.ToString());
    
                        lviSelectedPart.SubItems.Add(part.PartName);
                        lviSelectedPart.SubItems.Add(part.UnitPrice.ToString());
                        lviSelectedPart.SubItems.Add(txtQuantity.Text);
                        lviSelectedPart.SubItems.Add(txtSubTotal.Text);
                        lvwSelectedParts.Items.Add(lviSelectedPart);
                    }
                }
    
                CalculateOrder();
            }
    
            private void lvwSelectedParts_DoubleClick(object sender, EventArgs e)
            {
                ListViewItem lviSelectedPart = lvwSelectedParts.SelectedItems[0];
    
                if ((lvwSelectedParts.SelectedItems.Count == 0) ||
                    (lvwSelectedParts.SelectedItems.Count > 1))
                    return;
    
                txtPartNumber.Text = lviSelectedPart.Text;
                txtPartName.Text = lviSelectedPart.SubItems[1].Text;
                txtUnitPrice.Text = lviSelectedPart.SubItems[2].Text;
                txtQuantity.Text = lviSelectedPart.SubItems[3].Text;
                txtSubTotal.Text = lviSelectedPart.SubItems[4].Text;
    
                lvwSelectedParts.Items.Remove(lviSelectedPart);
                CalculateOrder();
            }
    
            private void tvwAutoParts_NodeMouseClick(object sender, TreeNodeMouseClickEventArgs e)
            {
                TreeNode nodClicked = e.Node!;
    
                if (nodClicked.Level == 4)
                    lvwAvailableParts.Items.Clear();
    
                try
                {
                    foreach (AutoPart part in AutoParts)
                    {
                        if ((part.Category == nodClicked.Text) &&
                            (part.Model == nodClicked.Parent!.Text) &&
                            (part.Make == nodClicked.Parent.Parent!.Text) &&
                            (part.Year.ToString() == nodClicked.Parent.Parent.Parent!.Text))
                        {
                            ListViewItem lviAutoPart = new ListViewItem(part.PartNumber.ToString());
    
                            lviAutoPart.SubItems.Add(part.PartName);
                            lviAutoPart.SubItems.Add(part.UnitPrice.ToString("F"));
                            lvwAvailableParts.Items.Add(lviAutoPart);
                        }
                    }
                }
                catch (NullReferenceException)
                {
                }
            }
    
            private void btnNewAutoPart_Click(object sender, EventArgs e)
            {
                StoreItemNew @new = new StoreItemNew();
    
                @new.ShowDialog();
    
                InitializeAutoParts();
            }
    
            private void btnAutoPartDetails_Click(object sender, EventArgs e)
            {
                StoreItemDetails details = new StoreItemDetails();
    
                details.Show();
            }
    
            private void btnAutoPartEditor_Click(object sender, EventArgs e)
            {
                StoreItemEditor editor = new StoreItemEditor();
    
                editor.ShowDialog();
    
                InitializeAutoParts();
            }
    
            private void btnDeleteAutoPart_Click(object sender, EventArgs e)
            {
                StoreItemDelete delete = new StoreItemDelete();
    
                delete.ShowDialog();
    
                InitializeAutoParts();
            }
    
            private void btnClose_Click(object sender, EventArgs e)
            {
                Close();
            }
        }
    }

21. To execute, on the main menu, click Debug and click Start Without Debugging:

    

22. Click the Delete Auto Part button:

    

23. In the Part # text box, type 928374
24. Click the Find Store Item button:

    

25. Click the Delete Auto Part button
26. On the Auto Part Deletion form, click the Close button
27. On the main form of the application, click the Close button

Example Application: Stellar Water Point

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