Control.OnClick(EventArgs) Methode

Definition

Namespace:

System.Windows.Forms

Assembly:

System.Windows.Forms.dll

Löst das Click-Ereignis aus.

protected:
 virtual void OnClick(EventArgs ^ e);

protected virtual void OnClick (EventArgs e);

abstract member OnClick : EventArgs -> unit
override this.OnClick : EventArgs -> unit

Protected Overridable Sub OnClick (e As EventArgs)

Parameter

e

EventArgs

Ein EventArgs, das die Ereignisdaten enthält.

Beispiele

Im folgenden Codebeispiel wird das Überschreiben der OnClick -Methode in einer abgeleiteten Klasse veranschaulicht. Fügen Sie zum Ausführen des Beispiels den folgenden Code nach einer Formularklasse in derselben Datei ein. Fügen Sie dem Formular ein Textfeld vom Typ SingleClickTextBox hinzu.

// This is a custom TextBox control that overrides the OnClick method
// to allow one-click selection of the text in the text box.
public ref class SingleClickTextBox: public TextBox
{
protected:
   virtual void OnClick( EventArgs^ e ) override
   {
      this->SelectAll();
      TextBox::OnClick( e );
   }
};

// This is a custom TextBox control that overrides the OnClick method
// to allow one-click selection of the text in the text box.

public class SingleClickTextBox: TextBox

{
    protected override void OnClick(EventArgs e)
    {
        this.SelectAll();
        base.OnClick(e);
    }
}

' This is a custom TextBox control that overrides the OnClick method
' to allow one-click selection of the text in the text box.

Public Class SingleClickTextBox
    Inherits TextBox

    Protected Overrides Sub OnClick(ByVal e As EventArgs)
        Me.SelectAll()
        MyBase.OnClick(e)
    End Sub


End Class

Das folgende Codebeispiel zeigt eine der vielen Verwendungen des Click Ereignis- und Ereignishandlers.

   // This example uses the Parent property and the Find method of Control to set
   // properties on the parent control of a Button and its Form. The example assumes
   // that a Button control named button1 is located within a GroupBox control. The 
   // example also assumes that the Click event of the Button control is connected to
   // the event handler method defined in the example.
private:
   void button1_Click( Object^ /*sender*/, System::EventArgs^ /*e*/ )
   {
      // Get the control the Button control is located in. In this case a GroupBox.
      Control^ control = button1->Parent;
      
      // Set the text and backcolor of the parent control.
      control->Text = "My Groupbox";
      control->BackColor = Color::Blue;
      
      // Get the form that the Button control is contained within.
      Form^ myForm = button1->FindForm();
      
      // Set the text and color of the form containing the Button.
      myForm->Text = "The Form of My Control";
      myForm->BackColor = Color::Red;
   }

// This example uses the Parent property and the Find method of Control to set
// properties on the parent control of a Button and its Form. The example assumes
// that a Button control named button1 is located within a GroupBox control. The 
// example also assumes that the Click event of the Button control is connected to
// the event handler method defined in the example.
private void button1_Click(object sender, System.EventArgs e)
{
   // Get the control the Button control is located in. In this case a GroupBox.
   Control control = button1.Parent;
   // Set the text and backcolor of the parent control.
   control.Text = "My Groupbox";
   control.BackColor = Color.Blue;
   // Get the form that the Button control is contained within.
   Form myForm = button1.FindForm();
   // Set the text and color of the form containing the Button.
   myForm.Text = "The Form of My Control";
   myForm.BackColor = Color.Red;
}

' This example uses the Parent property and the Find method of Control to set
' properties on the parent control of a Button and its Form. The example assumes
' that a Button control named button1 is located within a GroupBox control. The 
' example also assumes that the Click event of the Button control is connected to
' the event handler method defined in the example.
Private Sub button1_Click(sender As Object, e As System.EventArgs) Handles button1.Click
   ' Get the control the Button control is located in. In this case a GroupBox.
   Dim control As Control = button1.Parent
   ' Set the text and backcolor of the parent control.
   control.Text = "My Groupbox"
   control.BackColor = Color.Blue
   ' Get the form that the Button control is contained within.
   Dim myForm As Form = button1.FindForm()
   ' Set the text and color of the form containing the Button.
   myForm.Text = "The Form of My Control"
   myForm.BackColor = Color.Red
End Sub

Hinweise

Durch das Auslösen eines Ereignisses wird der Ereignishandler über einen Delegaten aufgerufen. Weitere Informationen finden Sie unter Behandeln und Auslösen von Ereignissen.

Mit der OnClick-Methode können auch abgeleitete Klassen das Ereignis ohne Anfügen eines Delegaten behandeln. Dies ist das bevorzugte Verfahren für die Behandlung des Ereignisses in einer abgeleiteten Klasse.

Hinweise für Vererber

Wenn Sie OnClick(EventArgs) in einer abgeleiteten Klasse überschreiben, müssen Sie die OnClick(EventArgs)-Methode der Basisklasse aufrufen, damit registrierte Delegaten das Ereignis empfangen.

Weitere Informationen

• Click