Control.OnDragEnter(DragEventArgs) 方法

定义

引发 DragEnter 事件。Raises the DragEnter event.

protected:
 virtual void OnDragEnter(System::Windows::Forms::DragEventArgs ^ drgevent);
protected virtual void OnDragEnter (System.Windows.Forms.DragEventArgs drgevent);
abstract member OnDragEnter : System.Windows.Forms.DragEventArgs -> unit
override this.OnDragEnter : System.Windows.Forms.DragEventArgs -> unit
Protected Overridable Sub OnDragEnter (drgevent As DragEventArgs)

参数

drgevent
DragEventArgs

包含事件数据的 DragEventArgsA DragEventArgs that contains the event data.

实现

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.

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

适用于

另请参阅