CommonDialog.HelpRequest Event


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Occurs when the user clicks the Help button on a common dialog box.

Namespace:   System.Windows.Forms
Assembly:  System.Windows.Forms (in System.Windows.Forms.dll)

Public Event HelpRequest As EventHandler

For information about handling events, see Handling and Raising Events.

The following code example demonstrates initializing a ColorDialog object setting the AnyColor, AllowFullOpen properties. The ColorDialog object does not allow the user to set a custom color, but it allows the full set of basic colors to be displayed. By setting the SolidColorOnly property to false, it allows the display of colors that are combinations of other colors on systems with 256 or less colors. The example also shows setting the ShowHelp property and handling a HelpRequest event for a dialog box. To run the example, paste the following code in a form and call the InitializeColorDialog method in the form's constructor or Load method. This example requires that the Click event of the button is connected to the event handler defined in the example.

' This method initializes ColorDialog1 to allow any colors, 
' and combination colors on systems with 256 colors or less, 
' but will not allow the user to set custom colors.  The
' dialog will contain the help button.
Private Sub InitializeColorDialog()
    Me.ColorDialog1 = New System.Windows.Forms.ColorDialog
    Me.ColorDialog1.AllowFullOpen = False
    Me.ColorDialog1.AnyColor = True
    Me.ColorDialog1.SolidColorOnly = False
    Me.ColorDialog1.ShowHelp = True
End Sub

' This method opens the dialog and checks the DialogResult value. 
' If the result is OK, the text box's background color will be changed 
' to the user-selected color.
Private Sub Button1_Click(ByVal sender As System.Object,  _
    ByVal e As System.EventArgs) Handles Button1.Click
    Dim result As DialogResult = ColorDialog1.ShowDialog()
    If (result.Equals(DialogResult.OK)) Then
        TextBox1.BackColor = ColorDialog1.Color
    End If
End Sub

' This method is called when the HelpRequest event is raised, 
'which occurs when the user clicks the Help button on the ColorDialog object.
Private Sub ColorDialog1_HelpRequest(ByVal sender As Object, _ 
    ByVal e As System.EventArgs) Handles ColorDialog1.HelpRequest

    MessageBox.Show("Please select a color by clicking it." _
    & "This will change the BackColor property of the TextBox.")
End Sub

.NET Framework
Available since 1.1
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