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

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 DragEventArgs 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