DataControlField.OnFieldChanged 方法

protected:
 virtual void OnFieldChanged();

protected virtual void OnFieldChanged ();

abstract member OnFieldChanged : unit -> unit
override this.OnFieldChanged : unit -> unit

Protected Overridable Sub OnFieldChanged ()

備註

OnFieldChanged方法會引發事件，通知物件的 DataControlField 狀態已變更。The OnFieldChanged method raises an event signaling that the DataControlField object's state has changed. 變更下列屬性會導致引發此事件： FooterText 、 HeaderImageUrl 、 HeaderText 、 ShowHeader 、 SortExpression 和 Visible 。Changes to the following properties cause this event to be raised: FooterText, HeaderImageUrl, HeaderText, ShowHeader, SortExpression, and Visible. 當狀態變更發生時，衍生型別屬性也會引發此事件。Derived type properties also raise this event when state changes occur. Web 服務器控制項（例如 DetailsView ） GridView 通常會呼叫 DataBind 方法來回應欄位變更事件。Web server controls such as DetailsView and GridView typically call the DataBind method in response to a field change event.

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.

OnFieldChanged 方法也允許衍生類別處理事件，而不用附加委派。The OnFieldChanged 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 OnFieldChanged() 時，請確定呼叫基底類別的 OnFieldChanged() 方法，使已註冊的委派能接收到事件。When overriding OnFieldChanged() in a derived class, be sure to call the base class's OnFieldChanged() method so that registered delegates receive the event.

適用於