CommonDialog.HelpRequest Evento

public:
 event EventHandler ^ HelpRequest;

public event EventHandler HelpRequest;

public event EventHandler? HelpRequest;

member this.HelpRequest : EventHandler 

Public Custom Event HelpRequest As EventHandler 

Tipo evento

Esempio

Nell'esempio di codice seguente viene illustrato l'inizializzazione di un ColorDialog oggetto che imposta le AnyColorproprietà , AllowFullOpen . L'oggetto ColorDialog non consente all'utente di impostare un colore personalizzato, ma consente di visualizzare il set completo di colori di base. Impostando la proprietà su false, consente la SolidColorOnly visualizzazione di colori che sono combinazioni di altri colori nei sistemi con 256 o meno colori. L'esempio mostra anche l'impostazione della proprietà e la ShowHelp gestione di un HelpRequest evento per una finestra di dialogo. Per eseguire l'esempio, incollare il codice seguente in un modulo e chiamare il InitializeColorDialog metodo nel costruttore o Load nel metodo del modulo. In questo esempio è necessario che l'evento Click del pulsante sia connesso al gestore eventi definito nell'esempio.

// 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." );
}

// 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.");
}

   
   ' 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

Commenti

Per informazioni sulla gestione degli eventi, vedere Gestione e generazione di eventi.

Si applica a

Vedi anche

• OnHelpRequest(EventArgs)