Control.OnKeyUp(KeyEventArgs) 方法

protected:
 virtual void OnKeyUp(System::Windows::Forms::KeyEventArgs ^ e);

protected virtual void OnKeyUp (System.Windows.Forms.KeyEventArgs e);

abstract member OnKeyUp : System.Windows.Forms.KeyEventArgs -> unit
override this.OnKeyUp : System.Windows.Forms.KeyEventArgs -> unit

Protected Overridable Sub OnKeyUp (e As KeyEventArgs)

参数

示例

下面的代码示例将 KeyUp 事件与类一起使用， Help 以便向用户显示弹出式样式帮助。The following code example uses the KeyUp event with the Help class to display pop-up style help to the user.

   // This example demonstrates how to use the KeyUp event with the Help class to display
   // pop-up style help to the user of the application. When the user presses F1, the Help
   // class displays a pop-up window, similar to a ToolTip, near the control. This example assumes
   // that a TextBox control, named textBox1, has been added to the form and its KeyUp
   // event has been connected to this event handler method.
private:
   void textBox1_KeyUp( Object^ /*sender*/, System::Windows::Forms::KeyEventArgs^ e )
   {
      
      // Determine whether the key entered is the F1 key. Display help if it is.
      if ( e->KeyCode == Keys::F1 )
      {
         
         // Display a pop-up help topic to assist the user.
         Help::ShowPopup( textBox1, "Enter your first name", Point(textBox1->Right,this->textBox1->Bottom) );
      }
   }

// This example demonstrates how to use the KeyUp event with the Help class to display
// pop-up style help to the user of the application. When the user presses F1, the Help
// class displays a pop-up window, similar to a ToolTip, near the control. This example assumes
// that a TextBox control, named textBox1, has been added to the form and its KeyUp
// event has been contected to this event handler method.
private void textBox1_KeyUp(object sender, System.Windows.Forms.KeyEventArgs e)
{
    // Determine whether the key entered is the F1 key. Display help if it is.
    if(e.KeyCode == Keys.F1)
    {
        // Display a pop-up help topic to assist the user.
        Help.ShowPopup(textBox1, "Enter your first name", new Point(textBox1.Right, this.textBox1.Bottom));
    }
}

' This example demonstrates how to use the KeyUp event with the Help class to display
' pop-up style help to the user of the application. When the user presses F1, the Help
' class displays a pop-up window, similar to a ToolTip, near the control. This example assumes
' that a TextBox control, named textBox1, has been added to the form and its KeyUp
' event has been contected to this event handler method.
Private Sub textBox1_KeyUp(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles textBox1.KeyUp
    ' Determine whether the key entered is the F1 key. Display help if it is.
    If e.KeyCode = Keys.F1 Then
        ' Display a pop-up help topic to assist the user.
        Help.ShowPopup(textBox1, "Enter your first name", New Point(textBox1.Right, Me.textBox1.Bottom))
    End If
End Sub

注解

引发事件时，将通过委托调用事件处理程序。Raising an event invokes the event handler through a delegate. 有关详细信息，请参阅 处理和引发事件。For more information, see Handling and Raising Events.

OnKeyUp 方法还允许派生类对事件进行处理而不必附加委托。The OnKeyUp method also allows derived classes to handle the event without attaching a delegate. 这是在派生类中处理事件的首选技术。This is the preferred technique for handling the event in a derived class.

继承者说明

在派生类中重写 OnKeyUp(KeyEventArgs) 时，一定要调用基类的 OnKeyUp(KeyEventArgs) 方法，以便已注册的委托对事件进行接收。When overriding OnKeyUp(KeyEventArgs) in a derived class, be sure to call the base class's OnKeyUp(KeyEventArgs) method so that registered delegates receive the event.

适用于

另请参阅

• KeyUp