WebClient.OpenWriteCompleted Evento

Definizione

Spazio dei nomi:

System.Net

Assembly:

System.Net.WebClient.dll

Source:

WebClient.cs

Si verifica al completamento di un'operazione asincrona di apertura di un flusso per la scrittura in una risorsa.

public:
 event System::Net::OpenWriteCompletedEventHandler ^ OpenWriteCompleted;

public event System.Net.OpenWriteCompletedEventHandler? OpenWriteCompleted;

member this.OpenWriteCompleted : System.Net.OpenWriteCompletedEventHandler 

Public Custom Event OpenWriteCompleted As OpenWriteCompletedEventHandler 

Tipo evento

OpenWriteCompletedEventHandler

Esempio

Nell'esempio di codice seguente viene illustrata l'impostazione di un gestore eventi per questo evento.

void OpenResourceForWriting2( String^ address )
{
   WebClient^ client = gcnew WebClient;
   Uri ^uri = gcnew Uri(address);

   // Specify that the OpenWriteCallback method gets called
   // when the writeable stream is available.
   client->OpenWriteCompleted += gcnew OpenWriteCompletedEventHandler( OpenWriteCallback2 );
   client->OpenWriteAsync( uri, "POST" );

   // Applications can perform other tasks
   // while waiting for the upload to complete.
}

public static void OpenResourceForWriting2(string address)
{
    WebClient client = new WebClient();
    Uri uri = new Uri(address);

    // Specify that the OpenWriteCallback method gets called
    // when the writeable stream is available.
    client.OpenWriteCompleted += new OpenWriteCompletedEventHandler(OpenWriteCallback2);
    client.OpenWriteAsync(uri, "POST");
    // Applications can perform other tasks
    // while waiting for the upload to complete.
}

Public Shared Sub OpenResourceForWriting2(ByVal address As String)

    Dim client As WebClient = New WebClient()

    '  Specify that the OpenWriteCallback method gets called
    '  when the writeable stream is available.
    AddHandler client.OpenWriteCompleted, AddressOf OpenWriteCallback2
                Dim uri as Uri = New Uri(address)
    client.OpenWriteAsync(uri, "POST")
    '  Applications can perform other tasks
    '  while waiting for the upload to complete.
End Sub

Nell'esempio di codice seguente viene illustrata un'implementazione di un gestore per questo evento.

void OpenWriteCallback2( Object^ /*sender*/, OpenWriteCompletedEventArgs^ e )
{
   Stream^ body = nullptr;
   StreamWriter^ s = nullptr;
   try
   {
      body = dynamic_cast<Stream^>(e->Result);
      s = gcnew StreamWriter( body );
      s->AutoFlush = true;
      s->Write( "This is content data to be sent to the server." );
   }
   finally
   {
      if ( s != nullptr )
      {
         s->Close();
      }
      if ( body != nullptr )
      {
         body->Close();
      }
   }

}

private static void OpenWriteCallback2(Object sender, OpenWriteCompletedEventArgs e)
{
    Stream body = null;
    StreamWriter s = null;

    try
    {
        body = (Stream)e.Result;
        s = new StreamWriter(body);
        s.AutoFlush = true;
        s.Write("This is content data to be sent to the server.");
    }
    finally
    {
        if (s != null)
        {
            s.Close();
        }

        if (body != null)
        {
            body.Close();
        }
    }
}

Private Shared Sub OpenWriteCallback2(ByVal sender As Object, ByVal e As OpenWriteCompletedEventArgs)

    Dim body As Stream = Nothing
    Dim s As StreamWriter = Nothing

    Try

        body = CType(e.Result, Stream)
        s = New StreamWriter(body)
        s.AutoFlush = True
        s.Write("This is content data to be sent to the server.")
    Finally

        If Not s Is Nothing Then

            s.Close()
        End If

        If Not body Is Nothing Then

            body.Close()
        End If
    End Try
End Sub

Commenti

Questo evento viene generato ogni volta che un'operazione asincrona consente di aprire un flusso usato per inviare dati a una risorsa completata. Queste operazioni vengono avviate chiamando i OpenWriteAsync metodi .

OpenWriteCompletedEventHandler è il delegato per questo evento. La OpenWriteCompletedEventArgs classe fornisce al gestore eventi i dati dell'evento.

Per altre informazioni su come gestire gli eventi, vedere la gestione e generazione di eventi.