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CommonDialog.HelpRequest Event

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

[Visual Basic]
Public Event HelpRequest As EventHandler
[C#]
public event EventHandler HelpRequest;
[C++]
public: __event EventHandler* HelpRequest;

[JScript] In JScript, you can handle the events defined by a class, but you cannot define your own.

Event Data

The event handler receives an argument of type EventArgs.

Remarks

For information about handling events, see Consuming Events.

Example

[Visual Basic, C#] The example shows setting the ShowHelp property and handling a HelpRequest event for a ColorDialog. 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 assumes the Click event of the button is connected to the event handling method defined in the example.

[Visual Basic] 

' 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

[C#] 
// 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 void InitializeColorDialog()
{
    this.ColorDialog1 = new System.Windows.Forms.ColorDialog();
    this.ColorDialog1.AllowFullOpen = false;
    this.ColorDialog1.AnyColor = true;
    this.ColorDialog1.SolidColorOnly = false;
    this.ColorDialog1.ShowHelp = true;
    
    // Associate the event-handling method with
    // the HelpRequest event.
    this.ColorDialog1.HelpRequest 
        += new System.EventHandler(ColorDialog1_HelpRequest);
}


// 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 void Button1_Click(System.Object sender, System.EventArgs e)
{
    DialogResult result = ColorDialog1.ShowDialog();
    if (result.Equals(DialogResult.OK))
    {
        TextBox1.BackColor = ColorDialog1.Color;
    }
}

// This method is called when the HelpRequest event is raised, 
//which occurs when the user clicks the Help button on the ColorDialog object.
private void ColorDialog1_HelpRequest(object sender, System.EventArgs e)
{

    MessageBox.Show("Please select a color by clicking it. "
       + "This will change the BackColor property of the TextBox.");
}

[C++, JScript] No example is available for C++ or JScript. To view a Visual Basic or C# example, click the Language Filter button Language Filter in the upper-left corner of the page.

Requirements

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family

See Also

CommonDialog Class | CommonDialog Members | System.Windows.Forms Namespace | OnHelpRequest

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