WebClient.DownloadDataCompleted 事件

定义

在异步数据下载操作完成时发生。Occurs when an asynchronous data download operation completes.

public:
 event System::Net::DownloadDataCompletedEventHandler ^ DownloadDataCompleted;
public event System.Net.DownloadDataCompletedEventHandler DownloadDataCompleted;
member this.DownloadDataCompleted : System.Net.DownloadDataCompletedEventHandler 
Public Event DownloadDataCompleted As DownloadDataCompletedEventHandler 

示例

下面的代码示例演示如何为此事件设置事件处理程序。The following code example demonstrates setting an event handler for this event.

// Sample call : DownLoadDataInBackground ("http://www.contoso.com/GameScores.html");
void DownloadDataInBackground( String^ address )
{
   System::Threading::AutoResetEvent^ waiter = gcnew System::Threading::AutoResetEvent( false );
   WebClient^ client = gcnew WebClient;
   Uri ^uri = gcnew Uri(address);
   
   // Specify that the DownloadDataCallback method gets called
   // when the download completes.
   client->DownloadDataCompleted += gcnew DownloadDataCompletedEventHandler( DownloadDataCallback );
   client->DownloadDataAsync( uri, waiter );
   
   // Block the main application thread. Real applications
   // can perform other tasks while waiting for the download to complete.
   waiter->WaitOne();
}


// Sample call : DownLoadDataInBackground ("http://www.contoso.com/GameScores.html");
public static void DownloadDataInBackground (string address)
{
    System.Threading.AutoResetEvent waiter = new System.Threading.AutoResetEvent (false);
    WebClient client = new WebClient ();
    Uri uri = new Uri(address);

    // Specify that the DownloadDataCallback method gets called
    // when the download completes.
    client.DownloadDataCompleted += new DownloadDataCompletedEventHandler (DownloadDataCallback);
    client.DownloadDataAsync (uri, waiter);

    // Block the main application thread. Real applications
    // can perform other tasks while waiting for the download to complete.
    waiter.WaitOne ();
}

'  Sample call : DownLoadDataInBackground ("http:' www.contoso.com/GameScores.html")
Public Shared Sub DownloadDataInBackground(ByVal address As String)

    Dim waiter As System.Threading.AutoResetEvent = New System.Threading.AutoResetEvent(False)
    Dim client As WebClient = New WebClient()

    '  Specify that the DownloadDataCallback method gets called
    '  when the download completes.
    AddHandler client.DownloadDataCompleted, AddressOf DownloadDataCallback
                Dim uri as Uri = New Uri(address)
    client.DownloadDataAsync(uri, waiter)

    '  Block the main application thread. Real applications
    '  can perform other tasks while waiting for the download to complete.
    waiter.WaitOne()
End Sub

注解

每次异步数据下载操作完成时都会引发此事件。This event is raised each time an asynchronous data download operation completes. 异步数据下载通过调用 DownloadDataAsync 方法来启动。Asynchronous data downloads are started by calling the DownloadDataAsync methods.

DownloadDataCompletedEventHandler 是此事件的委托。The DownloadDataCompletedEventHandler is the delegate for this event. DownloadDataCompletedEventArgs 类向事件处理程序提供事件数据。The DownloadDataCompletedEventArgs class provides the event handler with event data.

有关如何处理事件的详细信息,请参阅处理和引发事件For more information about how to handle events, see Handling and Raising Events.

适用于