OpenWriteCompletedEventHandler Delegat

Definition

Namespace:

System.Net

Assembly:

System.dll

Stellt die Methode dar, die das OpenWriteCompleted Ereignis eines .WebClient

public delegate void OpenWriteCompletedEventHandler(System::Object ^ sender, OpenWriteCompletedEventArgs ^ e);

public delegate void OpenWriteCompletedEventHandler(object sender, OpenWriteCompletedEventArgs e);

type OpenWriteCompletedEventHandler = delegate of obj * OpenWriteCompletedEventArgs -> unit

Public Delegate Sub OpenWriteCompletedEventHandler(sender As Object, e As OpenWriteCompletedEventArgs)

Parameter

sender

Object

Die Quelle des Ereignisses.

e

OpenWriteCompletedEventArgs

Eine OpenWriteCompletedEventArgs enthaltende Ereignisdaten.

Beispiele

Das folgende Codebeispiel veranschaulicht das Öffnen eines Datenstroms zum Schreiben von Daten, die hochgeladen werden sollen.

public static void OpenResourceForPosting(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);
    // Applications can perform other tasks
    // while waiting for the upload to complete.
}

Public Shared Sub OpenResourceForPosting(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)
    '  Applications can perform other tasks
    '  while waiting for the upload to complete.
End Sub

Die folgende Methode wird aufgerufen, wenn der Datenstrom verfügbar ist.

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

Hinweise

Wenn Sie einen OpenWriteCompletedEventHandler Delegaten erstellen, identifizieren Sie die Methode, die das Ereignis behandelt. Um das Ereignis dem Ereignishandler zuzuordnen, fügen Sie dem Ereignis eine Instanz des Delegaten hinzu. Der Ereignishandler wird immer dann aufgerufen, wenn das Ereignis auftritt, es sei denn, Sie entfernen den Delegaten.

Erweiterungsmethoden

Name	Beschreibung
GetMethodInfo(Delegate)	Ruft ein Objekt ab, das die vom angegebenen Delegaten dargestellte Methode darstellt.