WebClient.OpenWriteCompleted Событие

Определение

Пространство имен:

System.Net

Сборка:

System.Net.WebClient.dll

Исходный код:

WebClient.cs

Происходит после завершения асинхронной операции по записи данных в ресурс.

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

public event System.Net.OpenWriteCompletedEventHandler? OpenWriteCompleted;

member this.OpenWriteCompleted : System.Net.OpenWriteCompletedEventHandler 

Public Custom Event OpenWriteCompleted As OpenWriteCompletedEventHandler 

Тип события

OpenWriteCompletedEventHandler

Примеры

В следующем примере кода демонстрируется настройка обработчика событий для этого события.

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

В следующем примере кода показана реализация обработчика для этого события.

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

Комментарии

Это событие возникает при каждом завершении асинхронной операции открытия потока, используемого для отправки данных в ресурс. Эти операции запускаются путем OpenWriteAsync вызова методов .

Является OpenWriteCompletedEventHandler делегатом для этого события. Класс OpenWriteCompletedEventArgs предоставляет обработчику событий данные о событиях.

Дополнительные сведения об обработке событий см. в разделе Обработка и создание событий.