Socket.EndReceiveFrom(IAsyncResult, EndPoint) Método

Definição

Termina uma leitura assíncrona pendente de um ponto de extremidade específico.Ends a pending asynchronous read from a specific endpoint.

public:
 int EndReceiveFrom(IAsyncResult ^ asyncResult, System::Net::EndPoint ^ % endPoint);
public:
 int EndReceiveFrom(IAsyncResult ^ result, System::Net::EndPoint ^ % end_point);
public int EndReceiveFrom (IAsyncResult asyncResult, ref System.Net.EndPoint endPoint);
public int EndReceiveFrom (IAsyncResult result, ref System.Net.EndPoint end_point);
member this.EndReceiveFrom : IAsyncResult * EndPoint -> int
member this.EndReceiveFrom : IAsyncResult * EndPoint -> int
Public Function EndReceiveFrom (asyncResult As IAsyncResult, ByRef endPoint As EndPoint) As Integer
Public Function EndReceiveFrom (result As IAsyncResult, ByRef end_point As EndPoint) As Integer

Parâmetros

asyncResultresult
IAsyncResult

Um IAsyncResult que armazena informações de estado e dados definidos pelo usuário para essa operação assíncrona.An IAsyncResult that stores state information and any user defined data for this asynchronous operation.

endPointend_point
EndPoint

A fonte de EndPoint.The source EndPoint.

Retornos

Int32

Se tiver êxito, o número de bytes recebidos.If successful, the number of bytes received. Caso contrário, retornará 0.If unsuccessful, returns 0.

Exceções

asyncResult é null.asyncResult is null.

O EndReceiveFrom(IAsyncResult, EndPoint) foi chamado anteriormente para a leitura assíncrona.EndReceiveFrom(IAsyncResult, EndPoint) was previously called for the asynchronous read.

Ocorreu um erro ao tentar acessar o soquete.An error occurred when attempting to access the socket.

O Socket foi fechado.The Socket has been closed.

Exemplos

O exemplo de código a seguir Finaliza uma leitura assíncrona pendente de um específico EndPoint .The following code example ends a pending asynchronous read from a specific EndPoint.

StateObject^ so = safe_cast<StateObject^>(ar->AsyncState);
Socket^ s = so->workSocket;

// Creates a temporary EndPoint to pass to EndReceiveFrom.
IPEndPoint^ sender = gcnew IPEndPoint( IPAddress::Any,0 );
EndPoint^ tempRemoteEP = safe_cast<EndPoint^>(sender);

int read = s->EndReceiveFrom( ar, tempRemoteEP );

if ( read > 0 )
{
   so->sb->Append( Encoding::ASCII->GetString( so->buffer, 0, read ) );
   s->BeginReceiveFrom( so->buffer, 0, StateObject::BUFFER_SIZE, SocketFlags::None,
      tempRemoteEP, gcnew AsyncCallback( &Async_Send_Receive::ReceiveFrom_Callback ), so );
}
else
{
   if ( so->sb->Length > 1 )
   {
      //All the data has been read, so displays it to the console.
      String^ strContent = so->sb->ToString();
      Console::WriteLine( "Read {0} byte from socket" +
         " data = {1}", strContent->Length, strContent );
   }
   s->Close();
}
StateObject so = (StateObject) ar.AsyncState;
Socket s = so.workSocket;

   // Creates a temporary EndPoint to pass to EndReceiveFrom.
   IPEndPoint sender = new IPEndPoint(IPAddress.Any, 0);
EndPoint tempRemoteEP = (EndPoint)sender;

   int read = s.EndReceiveFrom(ar, ref tempRemoteEP);

if (read > 0) {
        so.sb.Append(Encoding.ASCII.GetString(so.buffer, 0, read));
        s.BeginReceiveFrom(so.buffer, 0, StateObject.BUFFER_SIZE, 0, ref tempRemoteEP,
                                 new AsyncCallback(Async_Send_Receive.ReceiveFrom_Callback), so);
}
else{
     if (so.sb.Length > 1) {
          //All the data has been read, so displays it to the console.
          string strContent;
          strContent = so.sb.ToString();
          Console.WriteLine(String.Format("Read {0} byte from socket" +
                           "data = {1} ", strContent.Length, strContent));
     }
     s.Close();
}
   Dim so As StateObject = CType(ar.AsyncState, StateObject)
   Dim s As Socket = so.workSocket
   
   ' Creates a temporary EndPoint to pass to EndReceiveFrom.
   Dim sender As New IPEndPoint(IPAddress.Any, 0)
   Dim tempRemoteEP As EndPoint = CType(sender, EndPoint)
   
   Dim read As Integer = s.EndReceiveFrom(ar, tempRemoteEP)
   
   
   If read > 0 Then
      so.sb.Append(Encoding.ASCII.GetString(so.buffer, 0, read))
      s.BeginReceiveFrom(so.buffer, 0, StateObject.BUFFER_SIZE, 0, tempRemoteEP, New AsyncCallback(AddressOf Async_Send_Receive.ReceiveFrom_Callback), so)
   Else
      If so.sb.Length > 1 Then
         'All the data has been read, so displays it to the console.
         Dim strContent As String
         strContent = so.sb.ToString()
         Console.WriteLine([String].Format("Read {0} byte from socket" + "data = {1} ", strContent.Length, strContent))
      End If
      s.Close()
   End If 
End Sub

Comentários

O EndReceiveFrom método conclui a operação de leitura assíncrona iniciada no BeginReceiveFrom método.The EndReceiveFrom method completes the asynchronous read operation started in the BeginReceiveFrom method.

Antes de chamar BeginReceiveFrom , você precisa criar um método de retorno de chamada que implemente o AsyncCallback delegado.Before calling BeginReceiveFrom, you need to create a callback method that implements the AsyncCallback delegate. Esse método de retorno de chamada é executado em um thread separado e é chamado pelo sistema após o BeginReceiveFrom retornos.This callback method executes in a separate thread and is called by the system after BeginReceiveFrom returns. O método de retorno de chamada deve aceitar o IAsyncResult retornado pelo BeginReceiveFrom método como um parâmetro.The callback method must accept the IAsyncResult returned by the BeginReceiveFrom method as a parameter.

No método de retorno de chamada, chame o AsyncState método do IAsyncResult para obter o objeto de estado passado para o BeginReceiveFrom método.Within the callback method, call the AsyncState method of the IAsyncResult to obtain the state object passed to the BeginReceiveFrom method. Extraia o recebimento deste Socket objeto de estado.Extract the receiving Socket from this state object. Depois de obter o Socket , você pode chamar o EndReceiveFrom método para concluir a operação de leitura com êxito e retornar o número de bytes lidos.After obtaining the Socket, you can call the EndReceiveFrom method to successfully complete the read operation and return the number of bytes read.

O EndReceiveFrom método será bloqueado até que os dados estejam disponíveis.The EndReceiveFrom method will block until data is available. Se você estiver usando um protocolo sem conexão, EndReceiveFrom o lerá o primeiro datagrama enfileirado disponível no buffer de rede de entrada.If you are using a connectionless protocol, EndReceiveFrom will read the first enqueued datagram available in the incoming network buffer. Se você estiver usando um protocolo orientado a conexão, o EndReceiveFrom método lerá o máximo de dados que está disponível até o número de bytes especificado no size parâmetro do BeginReceiveFrom método.If you are using a connection-oriented protocol, the EndReceiveFrom method will read as much data as is available up to the number of bytes you specified in the size parameter of the BeginReceiveFrom method. Se o host remoto desligar a Socket conexão com o Shutdown método e todos os dados disponíveis tiverem sido recebidos, o EndReceiveFrom método será concluído imediatamente e retornará zero bytes.If the remote host shuts down the Socket connection with the Shutdown method, and all available data has been received, the EndReceiveFrom method will complete immediately and return zero bytes. Para obter os dados recebidos, chame o AsyncState método do IAsyncResult objeto e extraia o buffer contido no objeto de estado resultante.To obtain the received data, call the AsyncState method of the IAsyncResult object, and extract the buffer contained in the resulting state object. Para identificar o host de origem, extraia o EndPoint e converta-o em um IPEndPoint .To identify the originating host, extract the EndPoint and cast it to an IPEndPoint. Use o IPEndPoint.Address método para obter o endereço IP e o IPEndPoint.Port método para obter o número da porta.Use the IPEndPoint.Address method to obtain the IP address and the IPEndPoint.Port method to obtain the port number.

Observação

Se você receber um SocketException , use a SocketException.ErrorCode propriedade para obter o código de erro específico.If you receive a SocketException, use the SocketException.ErrorCode property to obtain the specific error code. Depois de obter esse código, consulte a documentação do código de erro da API do Windows Sockets versão 2 para obter uma descrição detalhada do erro.After you have obtained this code, refer to the Windows Sockets version 2 API error code documentation for a detailed description of the error.

Observação

Esse membro emite o rastreamento de informações quando você ativa o rastreamento de rede em seu aplicativo.This member outputs trace information when you enable network tracing in your application. Para obter mais informações, consulte rastreamento de rede na .NET Framework.For more information, see Network Tracing in the .NET Framework.

Aplica-se a