Microsoft Certification Exam: 70-526 (MCTS)
Objective: Create and use custom dialog boxes in Windows Forms applications.
Language: Visual Basic 2005 (click here for the C# version of this entry)

I remember the first time I needed to create a dialog box in a .NET application that I was writing in C#. Being a long-time Visual Basic programmer, I assumed that this could easily be accomplished by using a dialog box template included with Visual Studio.NET. To my surprise, no such form template existed for C#, although one does for Visual Basic 2005. After wading through several books and Web pages filled with information on Windows Forms 2.0 programming, a basic set of steps became apparent to me for manually converting a .NET form into a Windows dialog box:

1. Add a Form to your .NET project and name it “DialogBoxForm”.

2. Drop two buttons in the lower right-hand area of the Form and name them “OKButton” and “CancelButton”.

3. Change the following properties of the Form to adjust its appearance and behavior to be like a standard dialog box:

Property	Value	Description
AcceptButton	OK button instance	Causes form to return value DialogResult.OK. Only used on modal dialog boxes.
CancelButton	Cancel button instance	Causes form to return value DialogResult.Cancel. Only used on modal dialog boxes.
FormBorderStyle	FixedDialog	Create a non-sizable form with no control box on the title bar.
HelpButton	True	The Help button appears in the caption bar next to the Close button. The ControlBox property must be True for these buttons to be visible.
MaximizeBox	False	Hide the Maximize button in the title bar.
MinimizeBox	False	Hide the Minimize button in the title bar.
ShowIcon	False	The title bar icon is not visible in a dialog box.
ShowInTaskBar	False	Do not indicate the presence of the form on the Windows Task Bar.
Start Position	CenterParent	The initial position of a dialog box is over its parent form.
Size	As Needed	The fixed size needed for the dialog box.

These properties can be set using the Properties window for the form, or using code placed in the Form’s Load event:

        Me.AcceptButton = OKButton
        Me.CancelButton = CancelButton
        Me.FormBorderStyle = Windows.Forms.FormBorderStyle.FixedDialog
        Me.HelpButton = True
        Me.MaximizeBox = False
        Me.MinimizeBox = False
        Me.ShowInTaskbar = False
        Me.ShowIcon = False
        Me.StartPosition = FormStartPosition.CenterParent

4. Add the following button click event handlers to the Form:

    Private Sub OKButton_Click(ByVal sender As Object, _    

     ByVal e As EventArgs)
        ‘ User clicked the OK button
        Me.DialogResult = Windows.Forms.DialogResult.OK
    End Sub    

    Private Sub CancelButton_Click(ByVal sender As Object, _    

     ByVal e As EventArgs)
        ‘ User clicked the Cancel button
        Me.DialogResult = Windows.Forms.DialogResult.Cancel
    End Sub

5. Add properties that you need to move data into and out of the dialog box as you would for any Form:

    Private _LoginName As String
    Private _LoginPassword As String    

    Public Property LoginName() As String
        Get
            Return _LoginName
        End Get
        Set(ByVal value As String)
            _LoginName = value
        End Set
    End Property    

    Public Property LoginPassword() As String
        Get
            Return _LoginPassword
        End Get
        Set(ByVal value As String)
            _LoginPassword = value
        End Set
    End Property

6. Show the dialog box modally by calling the ShowDialog() of the form:

    Public Sub ShowDialogBox()
        Dim dialog As New DialogBoxForm    

        dialog.LoginName = “JDMurray”
        dialog.LoginPassword = String.Empty    

        If dialog.ShowDialog() = Windows.Forms.DialogResult.OK Then
            Debug.WriteLine(“Login Name: “ & dialog.LoginName)
            Debug.WriteLine(“Password: “ & dialog.LoginPassword)
        Else
            ‘ User clicked the Cancel button
        End If
    End Sub

7. To show the dialog box modelessly, call the Show() method of DialogBoxForm instead. You will need to add an event handler to the Close event of DialogBoxForm to know when the user closes the dialog box:

    Public Sub ShowDialogBox()
        Dim dialog As DialogBoxForm = New DialogBoxForm
        dialog.LoginName = “JDMurray”
        dialog.Password = String.Empty
        AddHandler dialog.FormClosed, AddressOf dialog_FormClosed
        dialog.Show()    

        ‘ The Show() method returns immediately
    End Sub    

    Private Sub dialog_FormClosed(ByVal sender As Object, _    

     ByVal e As FormClosedEventArgs)
        ‘ This method is called when the user closes the dialog box
    End Sub

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This entry was posted on Tuesday, June 12th, 2007 at 6:26 pm and is filed under 70-526. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.