WebClient.OnDownloadFileCompleted(AsyncCompletedEventArgs) 方法

  • 參考

定義

命名空間:
System.Net
組件:
System.Net.WebClient.dll
組件:
System.dll
組件:
netstandard.dll
來源:
WebClient.cs
來源:
WebClient.cs
來源:
WebClient.cs

引發 DownloadFileCompleted 事件。

protected:
 virtual void OnDownloadFileCompleted(System::ComponentModel::AsyncCompletedEventArgs ^ e);
protected virtual void OnDownloadFileCompleted (System.ComponentModel.AsyncCompletedEventArgs e);
abstract member OnDownloadFileCompleted : System.ComponentModel.AsyncCompletedEventArgs -> unit
override this.OnDownloadFileCompleted : System.ComponentModel.AsyncCompletedEventArgs -> unit
Protected Overridable Sub OnDownloadFileCompleted (e As AsyncCompletedEventArgs)

參數

e
AsyncCompletedEventArgs

AsyncCompletedEventArgs 物件，包含事件資料。

範例

下列程式代碼範例示範這個方法的實作，這個方法可由衍生自 WebClient的類別自定義。

virtual void OnDownloadFileCompleted( System::ComponentModel::AsyncCompletedEventArgs ^ e ) override
{
   // Here you can perform any custom actions before the event is raised
   // and event handlers are called...
   WebClient::OnDownloadFileCompleted( e );

   // Here you can perform any post event actions...
}

protected  override void OnDownloadFileCompleted (System.ComponentModel.AsyncCompletedEventArgs e)
{
    // Here you can perform any custom actions before the event is raised
    // and event handlers are called...

    base.OnDownloadFileCompleted(e);

    // Here you can perform any post event actions...
}

備註

繼承自這個類別的類別可以覆寫這個方法，以在事件發生時 DownloadFileCompleted 執行其他工作。

引發事件會透過委派叫用此事件處理常式。 如需詳細資訊，請參閱 處理和引發事件。

OnDownloadFileCompleted 方法也允許衍生類別處理事件，而不用附加委派。 這是在衍生類別中處理事件的慣用技巧。

給繼承者的注意事項

在 OnDownloadFileCompleted(AsyncCompletedEventArgs) 衍生類別中覆寫時，請務必呼叫基類的 OnDownloadFileCompleted(AsyncCompletedEventArgs) 方法，讓已註冊的委派接收事件。

適用於