WebClient.OpenReadCompleted Evento

Definición

Espacio de nombres:

System.Net

Ensamblado:

System.Net.WebClient.dll

Source:

WebClient.cs

Se produce cuando se completa una operación asincrónica para abrir una secuencia que contiene un recurso.

public:
 event System::Net::OpenReadCompletedEventHandler ^ OpenReadCompleted;

public event System.Net.OpenReadCompletedEventHandler? OpenReadCompleted;

member this.OpenReadCompleted : System.Net.OpenReadCompletedEventHandler 

Public Custom Event OpenReadCompleted As OpenReadCompletedEventHandler 

Tipo de evento

OpenReadCompletedEventHandler

Ejemplos

En el ejemplo de código siguiente se muestra cómo establecer un controlador de eventos para este evento.

void OpenResourceForReading2( String^ address )
{
   WebClient^ client = gcnew WebClient;
   Uri ^uri = gcnew Uri(address);

   client->OpenReadCompleted += gcnew OpenReadCompletedEventHandler( OpenReadCallback2 );
   client->OpenReadAsync( uri );
}

public static void OpenResourceForReading2(string address)
{
    WebClient client = new WebClient();
    Uri uri = new Uri(address);

    client.OpenReadCompleted += new OpenReadCompletedEventHandler(OpenReadCallback2);
    client.OpenReadAsync(uri);
}

Public Shared Sub OpenResourceForReading2(ByVal address As String)

    Dim client As WebClient = New WebClient()
    AddHandler client.OpenReadCompleted, AddressOf OpenReadCallback2
                Dim uri as Uri = New Uri(address)
    client.OpenReadAsync(uri)
End Sub

En el ejemplo de código siguiente se muestra una implementación de un controlador para este evento.

void OpenReadCallback2( Object^ /*sender*/, OpenReadCompletedEventArgs^ e )
{
   Stream^ reply = nullptr;
   StreamReader^ s = nullptr;
   try
   {
      reply = dynamic_cast<Stream^>(e->Result);
      s = gcnew StreamReader( reply );
      Console::WriteLine( s->ReadToEnd() );
   }
   finally
   {
      if ( s != nullptr )
      {
         s->Close();
      }
      if ( reply != nullptr )
      {
         reply->Close();
      }
   }

}

private static void OpenReadCallback2(Object sender, OpenReadCompletedEventArgs e)
{
    Stream reply = null;
    StreamReader s = null;

    try
    {
        reply = (Stream)e.Result;
        s = new StreamReader(reply);
        Console.WriteLine(s.ReadToEnd());
    }
    finally
    {
        if (s != null)
        {
            s.Close();
        }

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

Private Shared Sub OpenReadCallback2(ByVal sender As Object, ByVal e As OpenReadCompletedEventArgs)

    Dim reply As Stream = Nothing
    Dim s As StreamReader = Nothing

    Try

        reply = CType(e.Result, Stream)
        s = New StreamReader(reply)
        Console.WriteLine(s.ReadToEnd())
    Finally

        If Not s Is Nothing Then

            s.Close()
        End If

        If Not reply Is Nothing Then

            reply.Close()
        End If
    End Try
End Sub

Comentarios

Cautela

WebRequest, HttpWebRequest, ServicePointy WebClient están obsoletos y no debe usarlos para el nuevo desarrollo. Use HttpClient en su lugar.

Este evento se genera cada vez que se completa una operación asincrónica para abrir una secuencia que contiene un recurso. Estas operaciones se inician llamando a los métodos OpenReadAsync.

El OpenReadCompletedEventHandler es el delegado de este evento. La clase OpenReadCompletedEventArgs proporciona al controlador de eventos datos de eventos.

Para obtener más información sobre cómo controlar eventos, vea Control y generación de eventos.