8. Project using Multiple Forms

In this lesson we will consider a project using four forms.   In VB, the Form is the container for all the controls that make up the user interface.   A form has a title bar , on which the form’s caption is displayed.  On the right side of the title bar are three buttons-Maximize, Minimize and Close.  Each form is designed to operate independently of the others, and they can communicate via global variables.  In other situations one form can be controlled from within another.   This means you can manipulate the properties of the controls in one form, from within another form. But you cannot capture the events of one form’s controls in another form.

Creating Forms:

When you open the Standard Exe window, you get the first form entitled as form1.   For adding a form select  ‘Add Form’ from the Project menu and then select the Form icon from the Add Form Dialog Window.   The second form is added, entitled as form2.   In a similar manner you can add any number of forms.  When the project is finally saved, you will be presented with form save dialog for each form.   You can give appropriate names for each of the forms.   Of course when the project is subsequently opened, all the forms in the project are automatically opened  and also saved when the project is saved.  

Description of the Forms:

The first form called the main form contains the titles of the other projects to which one can branch by clicking the appropriate button.   The layout of the main form (main.frm) is as shown in the figure 1.    It contains a menu bar with two titles, ‘File’ and ‘Options’.   The File Menu has only one item namely, ‘Exit’.   The Options menu has 3 items namely,  ‘Test Buttons’, Check Box’, and  ‘Option Buttons’..  It has 4 command buttons with their captions changed to ‘Test Buttons’, ‘Check Box’,  ‘Option Button’ and ‘Exit’ respectively.   The codes of the controls used in the main form are entered as shown in the figure 1a.    

                                   Figure 1

Private Sub cmdButtons_Click()

    ' invoke a Click event in the menu

    mnuButtons_Click

End Sub

Private Sub cmdCheck_Click()

    ' invoke a Click event in the menu

    mnuCheck_Click

End Sub

Private Sub cmdExit_Click()

    Unload Me       ' unload the form

    End             ' end the application

End Sub

Private Sub cmdOption_Click()

    ' invoke a Click event in the menu

    mnuOption_Click

End Sub

Private Sub Form_Load()

    frmMain.Height = 3600

    frmMain.Width = 4965

End Sub

Private Sub mnuButtons_Click()

    ' display the form

    frmButton.Show

End Sub

Private Sub mnuCheck_Click()

    ' display the form

    frmCheck.Show

End Sub

Private Sub mnuFileExit_Click()

    ' invoke a Click event in the command button

    cmdExit_Click

End Sub

Private Sub mnuOption_Click()

    ' display the form

    frmOptions.Show

End Sub

    Figure 1a