Control.OnClick(EventArgs) Metoda

Definice

Obor názvů:

System.Windows.Forms

Sestavení:

System.Windows.Forms.dll

Click Vyvolá událost.

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)

Parametry

e

EventArgs

Obsahující EventArgs data události.

Příklady

Následující příklad kódu ukazuje přepsání OnClick metody v odvozené třídě. Pokud chcete spustit příklad, vložte následující kód za třídu formuláře do stejného souboru. Přidejte do formuláře textové pole typu SingleClickTextBox .

// 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

Následující příklad kódu ukazuje jedno z mnoha použití události a obslužné Click rutiny události.

   // 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

Poznámky

Vyvolání události spustí obslužnou rutinu události prostřednictvím delegáta. Další informace najdete v tématu Zpracování a vyvolávání událostí.

Metoda OnClick také umožňuje odvozeným třídám zpracovat událost bez připojení delegáta. Toto je upřednostňovaná technika pro zpracování události v odvozené třídě.

Poznámky pro dědice

Při přepsání OnClick(EventArgs) v odvozené třídě nezapomeňte volat metodu základní třídy OnClick(EventArgs) , aby registrovaní delegáti obdrželi událost.

Viz také

• Click