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The Forms of a Database Application: The Properties of a Form

 

Introduction

A form appears as a rectangular object that occupies the necessary portion of the screen and is used to represent its application. A form by itself accomplishes little to no purpose. Its main role is revealed in its ability to be a container. That is, a form is mainly used to hold or host other controls. As a regular window, a form is equipped with a system icon, a title bar, one or more system buttons, borders, corners, and a body. Depending on the role of your form, you may want to design forms that present differing characteristics, even if these forms belong to the same database. For example, while one form presents a normal title bar, you may want another form not to present a title bar at all. While you may allow the user to be able to minimize or maximize a form, you may want to present one or both of these actions for the user. As an application design environment, Microsoft Access provides most of the features you will need for a regular and even advanced database product.

Referring to a Form

To refer to a form of a Microsoft Visual Basic application, you can use the Me keyword.

After creating a database, or while working on one, all of the forms that belong to it are stored in a collection called AllForms. As seen for the AllTables collection, AllForms is equipped with the Count property that holds the number of the forms that belong to the current database. Each form can be located by its name or its index, using the Item() property.

In Microsoft Access, a form is an object of type Form. A form that is opened in a database is a member of the Forms collection. To refer to an open form in your code, you can enter the Forms collection, followed by an exclamation point !, followed by the name of the form. Here is an example that refers to a form named Students:

Forms!Students

You can also include the name of the form between an opening square bracket and a closing square bracket but, if the name is in one word, then the square brackets are optional:

Forms![Students]

If the name is made of more than one word, then square brackets become required. Here is an example that refers to a form named Potential Applicants:

Forms![Potential Applicants]

If you omit the square brackets in this case, the expression or the code may not work.

A form can also be referred to by an index in the Forms collection. The first form of the collection has an index of 0 and can be accessed with Forms(0). The second form in the collection has an index of 1 and can be referred to by Forms(1), and so on. The name of the form can also be used as index. For example, a form named Students can be referred to as Forms("Students").

We mentioned that a form is mostly used as a container because it hosts some of the controls of its application. The controls that a form hosts are members of the Controls collection.

 

The Record Source

If a form has been designed or exists already but you want its Windows controls to display the values from a table, you can change its Record Source property to that of the table. After doing this, all columns from the table become available to controls on the form.

To programmatically specify the table that holds the data that would be made available to the controls on a form or a report, assign the name of the table to its RecordSource property. Here is an example:

Private Sub cmdRecordSource_Click()
    Me.RecordSource = "CleaningOrders"
End Sub
 

The System Menu

Like a regular window container, the form displays a title bar in its top section. On the left side of the title bar, it displays an icon. The system icon is fixed and you should not spend time trying to change it. The system icon holds a menu that allows the user to perform the regular operations of a Windows container, including minimizing, maximizing, restoring or closing the window. To display this menu, the user can click the formís system icon:

The presence of the formís system icon is partly controlled by the Control Box property of a form. In most cases, you should make this system icon and its menu available to the user. If for some reason you don't want to provide this functionality, set the Control Box property to No. The form would appear as follows:

If you decide to do this, make sure you provide the user with the ability to close the form and this type of title bar makes it impossible. Of course, a user may know that the form can be closed by clicking the Close menu item under the File group of the main menu or by pressing Ctrl + F4.

 

The Title Bar

The middle section of the title bar is actually referred to as the title bar. It can be used to change the view of the form after right-clicking it. The title bar uses a color set in the Advanced Appearance of Control Panel as Active Title Bar:

Since you cannot control and cannot predict how your users will modify their system colors (because most users are free to set their system colors as they wish, even when they work corporate), you should refrain from changing this color when designing your forms, especially if you plan to distribute your database. Otherwise, the result you see on your form may be different from your users computers.

When designing your forms, try to keep colors to their default and to their minimum. In this lesson, we are showing most options simply to let you know that they exist, not because you should or must change them.
 

The System Buttons

The right side of the formís title bar displays three system buttons Minimize , Maximize or Restore , Close . The group of these buttons is called the Control Box. If you do not want these system buttons at all, access the Properties window of the form and set the Control Box Boolean property to No from its Yes default value. In this case, the form would appear with neither the system icon nor the system buttons as seen above. Once again, if you do this, make sure the user has a way to close the form.

Instead of completely hiding all system buttons of a form, you can specify which ones to display and thus control the ability to close, minimize, or maximize the form. The presence and/or the role of the system buttons is (partly) controlled by the Control Box and the Min Max Buttons properties. When the Control Box property is set to No, regardless of the value of the Min Max Buttons property, there would be no system buttons on the title bar (this is also something you learn if you do Windows GUI programming, like Win32). Therefore, in order to control the appearance and behavior of the system buttons, the Control Box property must be set to Yes. The values of the Min Max Buttons produce the following results:

Min Max Buttons Result System Buttons Consequence
Minimize Maximize Close
None Hidden Hidden Available The form can only be closed
Min Enabled Enabled Disabled Available The form can be minimized or closed but not maximized
Max Enabled Disabled Enabled Available The form cannot be minimized but can be maximized
Both Enabled Enabled Enabled Available All operations (minimize, maximize, restore, and close) are allowed

Depending on the role and probably the number of Windows controls on a form, you will decide what button to allow or not.

To minimize a form, the user can click its Minimize button. To programmatically minimize a form, you can call the Minimize() method of the DoCmd object. Here is an example:

Private Sub cmdManipulate_Click()
    DoCmd.Minimize
End Sub

To maximize a form, the user can click its Maximize button. To programmatically maximize a form, you can call the Maximize() method of the DoCmd object. If a form is maximized, to restore it, the user can click the Restore button. To programmatically restore a form, call the Restore() button of the DoCmd object.

To close a form, the user can click its system Close button. As seen earlier, to close a form, you can call the DoCmd.Close method.

 

Practical Learning Practical Learning: Controlling the System Buttons of a Form

  1. To select the Central form, on the main menu, click Windows -> Central
  2. As the form is still in Design View, click the button at the intersection of its rulers
  3. In the Properties window, set its Min Max Buttons property to Min Enabled
  4. Save the form

The Formís Borders

Whether you allow the system icon and system buttons or not, the user needs to be able to know where a form starts and where it ends. This is seen by the borders of the form. In most cases, you will not be concerned with this aspect. Otherwise, you can control the borders of a form.

The borders of a form are controlled using the Border Style property. If you set it to None, the form would appear without borders:

 

The Form's Width

A form displays on the screen using its dimensions. These are the width and height. The form itself controls only the width. The height is controlled by its sections. To change the width of a form, in the Properties window, type the desired decimal value in the Width field of the Format property page. You can also change the form's width by dragging the right border of one of its sections.

 

The Detail Section

The most visible part of a form is an area called Detail. This section starts on a bar labeled Detail and ends at the bottom unless a new section starts. To programmatically access the Detail section of a form, if you working in an event of the form, you can use either Detail or Me.Detail

The Detail section serves as the main host of other controls. It can also serve to display messages of various kinds. The Detail section can be enhanced by manipulating its properties. These properties are not necessarily related to the parent form but can be used conjointly with it.

We mentioned earlier that the form itself controle its width. The vertical dimension of a form is controlled by its sections. This means that a section, such as the Detail section, can "decide" how much height it needs to accommodate its content. The vertical measurement of the Detail section is controlled by the Height property. There are two main ways you can change the Detail section's height at design time:

  • In the Format tab of the Properties window, you can change the value of the Height field. The value must be a natural or a decimal number. In reality it is a decimal number. If you type a natural number, also called an integer, it would be converted to decimal. If you type an invalid number, you would receive an error
  • You can position your mouse in the lower border of the Detail section until the mouse cursor changes into a vertical double arrow. Then click and drag. You can drag up to shrink the section or drag down to heighten it
     

To programmatically change the height of the Detail section, assign a constant natural or decimal value to its Height property. Here is an example:

Private Sub cmdChangeHeight_Click()
    Me.Detail.Height = 3.18
End Sub
 
 

The Header and Footer Sections

Besides the Detail section, a form can be enhanced with one or two more sections: Header and Footer.

By default, the Header and Footer sections are created on a form if you use the Form Wizard.

To add the Header and Footer sections on a form that doesn't have them, you can use the menu bar where you would click View -> Form Header/Footer. Probably the fastest way to add these sections is by right-clicking anywhere on the form and clicking Form Header/Footer. If the form already has these sections but they don't contain anything, they would be removed. If the form already has these sections and they contain anything, you would receive a warning:

If you still want to delete the Header and Footer sections, you can click Yes; this would un-recoverably delete their content.Like the Detail section, the Header and Footer sections control their own height, which you can change the same way we described above for the Detail section.

To access the Header section in your code, use the form's FormHeader property. Here is an example:

Private Sub cmdManipulate_Click()
    Me.FormHeader.Height = 2.24
End Sub

To programmatically access the Footer section, use the form's FormFooter property. 

 This also applies for the Back Color property. The Special Effect property allows you to raise or sink a section.

 

Practical Learning Practical Learning: Closing a Form

  1. To select a different form, on the main menu, click Windows -> Cleaning Orders
  2. To add the Header and Footer sections to the form, right-click the body of the form and click Form Header/Footer
  3. On the Toolbox, make sure the Control Wizards button is pushed , click Command Button and click the right section under the Footer bar of the form
  4. In the Categories list of the first page of the Command Button Wizard, click Form Operations
  5. In the Actions list, click Close Form, and click Next
  6. In the second page of the wizard, click the text box and change its string to Close
  7. Click Next
  8. Change the name of the button to cmdClose and click Finish
 

Record Selectors

The Record Selector is a vertical bar on the left side of a form. It allows the user to select all of the fieldsí contents of one or more records and copy them to the clipboard. Such a selection can then be pasted to another record, other records, or to a text or another type of file (for example you can paste the record in Notepad, Microsoft Word, Microsoft Excel, or any text file).

There are two reasons you would use record selectors on a form. If you want the user to be able to access all fields of a record as a whole, make sure that the form is equipped with record selectors. In the same way, you can hide the scroll bar if the user would not need them. Another reason you would use a record selector is for aesthetic reasons. Most of the time, if designing a form for data entry, you would mostly allow the presence of record selectors. If you are designing a dialog box that would display the same content all the time, you should not allow the record selectors.

The presence or absence of record selectors is controlled by the Boolean Record Selectors property field. If you set the field value to Yes, the form would display the record selector. Setting the field value to No would hide the record selectors. To programmatically control the presence or absence of the record selector on a form, assign a value of True (to display it) or False (to hide it) to the RecordSelector property of the form. Here is an example:
Private Sub cmdManipulate_Click()
    Me.RecordSelectors = False
End Sub
 

The Form's Scroll Bars

As much as you can, you should design your (non-Datasheet) form to display all of the fields of a record. Sometimes this will not be possible. If a form possesses too many fields, Microsoft Access would equip the form with one or two scroll bars. A scroll bar allows the user to scroll from one side of the form to another. The vertical scroll bar is used to scroll up and down while the horizontal scroll allows scrolling left and right.

By default, scroll bars come up if the form "judges" that some fields are hidden. The presence of scroll bars allows the user to be aware of hidden objects on the form. Depending on your design, you can control the appearance or disappearance of the scroll bars. To do this, change the value of the Scroll Bars field in the Format property page of the Properties window. There are four possible values. To display only the vertical scroll bar, set the value to Vertical Only. In the same way, you can display only the vertical scroll bar by selecting Horizontal Only. On the other hand, you can display both scroll bars by setting the value to Both. If for some reason you don't want any scroll bar, set the Scroll Bars property value to Neither.

To programmatically control the presence or absence of scroll bars, access the ScrollBars property of the form and assign one of the following four values:

Value Description
0 No scroll bar will display
1 Only the horizontal scroll bar will display
2 Only the vertical scroll bar will display
3 Both the horizontal and the vertical scroll bars will display
 
 

Navigation Buttons

When we study records, we will see that a form (also a table, a query, or a report) is equipped with some buttons in its lower section. These buttons allow the user to navigate back and forth between records. These buttons are very useful during data entry and data analysis. If you are creating a form that would display the same content all the time, such as a form that does not actually display records, you can hide the form navigation buttons.

The presence or absence of navigation buttons is controlled by the Boolean Navigation Buttons property. When its value is set to Yes, the form would display the Navigation Buttons. To hide them, set the Navigation Buttons property value to No.

To programmatically control the presence or absence of the navigation buttons, access the form's NavigationButtons property and assign the desired Boolean value. Here is an example:

Private Sub cmdManipulate_Click()
    Me.NavigationButtons = False
End Sub
 

Dividing Lines

A form is equipped with special horizontal lines used to visually separate sections of a form. They do not perform any other special function. They can be useful on a continuous form.

To equip a form with dividing lines, add a header and a footer sections. On the other hand, if you create a form that is directly equipped with a header and a footer sections, it would display the dividing lines.

The presence or absence of the horizontal lines is controlled by the Boolean Dividing Lines property. Its default value is Yes, which means that the dividing horizontal lines would display on the form. To hide both lines, you can set its value to No. To hide an individual line, you can completely reduce its section.

To control the presence or absence of the dividing lines of a form, access its DividingLines property and assign the desired Boolean value. Here is an example:

Private Sub cmdManipulate_Click()
    DividingLines = False
End Sub
 

Form Automatic Centering

By default, when a previously created and saved form appears, Microsoft Access remembers the previous position the form had and restores it. If you can make sure that the form is always centered when it comes up. To make this possible, the form is equipped with the Auto Center Boolean property. When set to Yes, this property causes the form to be centered when it displays to the user.

 

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