Control.OnPreviewKeyDown(PreviewKeyDownEventArgs) Control.OnPreviewKeyDown(PreviewKeyDownEventArgs) Control.OnPreviewKeyDown(PreviewKeyDownEventArgs) Control.OnPreviewKeyDown(PreviewKeyDownEventArgs) Method

定义

引发 PreviewKeyDown 事件。Raises the PreviewKeyDown event.

protected:
 virtual void OnPreviewKeyDown(System::Windows::Forms::PreviewKeyDownEventArgs ^ e);
protected virtual void OnPreviewKeyDown (System.Windows.Forms.PreviewKeyDownEventArgs e);
abstract member OnPreviewKeyDown : System.Windows.Forms.PreviewKeyDownEventArgs -> unit
override this.OnPreviewKeyDown : System.Windows.Forms.PreviewKeyDownEventArgs -> unit
Protected Overridable Sub OnPreviewKeyDown (e As PreviewKeyDownEventArgs)

参数

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.

OnPreviewKeyDown 方法还允许派生类对事件进行处理而不必附加委托。The OnPreviewKeyDown 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 OnPreviewKeyDown(PreviewKeyDownEventArgs) 时,一定要调用基类的 OnPreviewKeyDown(PreviewKeyDownEventArgs) 方法,以便已注册的委托对事件进行接收。When overriding OnPreviewKeyDown(PreviewKeyDownEventArgs) in a derived class, be sure to call the base class's OnPreviewKeyDown(PreviewKeyDownEventArgs) method so that registered delegates receive the event.

适用于