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CommonDialog::HelpRequest Event

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 EventHandler^ HelpRequest {
	void add (EventHandler^ value);
	void remove (EventHandler^ value);
}

For information about handling events, see Consuming 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. 
void InitializeColorDialog()
{
   this->ColorDialog1 = gcnew 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 +=
      gcnew System::EventHandler( this, &Form1::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. 
void Button1_Click( System::Object^ sender, System::EventArgs^ e )
{
   ::DialogResult result = ColorDialog1->ShowDialog();
   if ( result == ::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. 
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." );
}

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0
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