Control.OnDragEnter(DragEventArgs) Control.OnDragEnter(DragEventArgs) Control.OnDragEnter(DragEventArgs) Control.OnDragEnter(DragEventArgs) Method

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 DragEventArgs DragEventArgs 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