WebClient.OnDownloadDataCompleted(DownloadDataCompletedEventArgs) 方法

定义

引发 DownloadDataCompleted 事件。Raises the DownloadDataCompleted event.

protected:
 virtual void OnDownloadDataCompleted(System::Net::DownloadDataCompletedEventArgs ^ e);
protected virtual void OnDownloadDataCompleted (System.Net.DownloadDataCompletedEventArgs e);
abstract member OnDownloadDataCompleted : System.Net.DownloadDataCompletedEventArgs -> unit
override this.OnDownloadDataCompleted : System.Net.DownloadDataCompletedEventArgs -> unit
Protected Overridable Sub OnDownloadDataCompleted (e As DownloadDataCompletedEventArgs)

参数

e
DownloadDataCompletedEventArgs

包含事件数据的 DownloadDataCompletedEventArgs 对象。A DownloadDataCompletedEventArgs object that contains event data.

示例

下面的代码示例演示了此方法的一个实现,该实现可由派生自的类进行自定义 WebClientThe following code example shows an implementation of this method that can be customized by a class derived from WebClient.

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

   // Here you can perform any post event actions...
}
protected override void OnDownloadDataCompleted (DownloadDataCompletedEventArgs e)
{
    // Here you can perform any custom actions before the event is raised
    // and event handlers are called...

    base.OnDownloadDataCompleted(e);

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

注解

从此类继承的类可以重写此方法,以便在事件发生时执行其他任务 DownloadDataCompletedClasses that inherit from this class can override this method to perform additional tasks when the DownloadDataCompleted event occurs.

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

OnDownloadDataCompleted 方法还允许派生类对事件进行处理而不必附加委托。The OnDownloadDataCompleted 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

OnDownloadDataCompleted(DownloadDataCompletedEventArgs) 在派生类中重写时,请确保调用基类的 OnDownloadDataCompleted(DownloadDataCompletedEventArgs) 方法,以便注册的委托接收事件。When overriding OnDownloadDataCompleted(DownloadDataCompletedEventArgs) in a derived class, be sure to call the base class' OnDownloadDataCompleted(DownloadDataCompletedEventArgs) method so that registered delegates receive the event.

适用于