Control.OnDragEnter(DragEventArgs) 方法

定義

引發 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)

參數

drgevent
DragEventArgs

DragEventArgs,其中包含事件資料。A DragEventArgs that contains the event data.

實作

備註

引發事件會透過委派叫用此事件處理常式。Raising an event invokes the event handler through a delegate. 如需詳細資訊,請參閱處理和引發事件For more information, see Handling and Raising Events.

OnDragEnter 方法也允許衍生類別處理事件,而不用附加委派。The OnDragEnter method also allows derived classes to handle the event without attaching a delegate. 這是在衍生類別中處理事件的慣用技巧。This is the preferred technique for handling the event in a derived class.

給繼承者的注意事項

當在衍生類別中覆寫 OnDragEnter(DragEventArgs) 時,請確定呼叫基底類別的 OnDragEnter(DragEventArgs) 方法,使已註冊的委派能接收到事件。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.

適用於

另請參閱