MessageQueue.EndReceive(IAsyncResult) Method

Definition

Conclui a operação de recebimento assíncrono especificada.Completes the specified asynchronous receive operation.

public:
 System::Messaging::Message ^ EndReceive(IAsyncResult ^ asyncResult);
public System.Messaging.Message EndReceive (IAsyncResult asyncResult);
member this.EndReceive : IAsyncResult -> System.Messaging.Message
Public Function EndReceive (asyncResult As IAsyncResult) As Message

Parameters

asyncResult
IAsyncResult

O IAsyncResult que identifica a operação de recebimento assíncrono a concluir e da qual recuperar o resultado final.The IAsyncResult that identifies the asynchronous receive operation to finish and from which to retrieve an end result.

Returns

Message

O Message associado com a operação assíncrona concluída.The Message associated with the completed asynchronous operation.

Exceptions

O parâmetro asyncResult é null.The asyncResult parameter is null.

A sintaxe do parâmetro asyncResult não é válida.The syntax of the asyncResult parameter is not valid.

Erro ao acessar um método do serviço de Enfileiramento de Mensagens.An error occurred when accessing a Message Queuing method.

Examples

O exemplo de código a seguir encadeia solicitações assíncronas.The following code example chains asynchronous requests. Ele assume que há uma fila no computador local chamada "MyQueue".It assumes there is a queue on the local computer called "myQueue". A função Main inicia a operação assíncrona que é tratada pela rotina de MyReceiveCompleted.The Main function begins the asynchronous operation that is handled by the MyReceiveCompleted routine. MyReceiveCompleted processa a mensagem atual e inicia uma nova operação de recebimento assíncrono.MyReceiveCompleted processes the current message and begins a new asynchronous receive operation.

#using <system.dll>
#using <system.messaging.dll>

using namespace System;
using namespace System::Messaging;
using namespace System::Threading;

ref class MyNewQueue
{
public:

   // Define static class members.
   static ManualResetEvent^ signal = gcnew ManualResetEvent( false );
   static int count = 0;

   // Provides an event handler for the ReceiveCompleted
   // event.
   static void MyReceiveCompleted( Object^ source, ReceiveCompletedEventArgs^ asyncResult )
   {
      try
      {
         // Connect to the queue.
         MessageQueue^ mq = dynamic_cast<MessageQueue^>(source);

         // End the asynchronous receive operation.
         mq->EndReceive( asyncResult->AsyncResult );
         count += 1;
         if ( count == 10 )
         {
            signal->Set();
         }

         // Restart the asynchronous receive operation.
         mq->BeginReceive();
      }
      catch ( MessageQueueException^ ) 
      {
         // Handle sources of MessageQueueException.
      }

      // Handle other exceptions.
      return;
   }
};

// Provides an entry point into the application.
//         
// This example performs asynchronous receive
// operation processing.
int main()
{
   // Create an instance of MessageQueue. Set its formatter.
   MessageQueue^ myQueue = gcnew MessageQueue( ".\\myQueue" );
   array<Type^>^p = gcnew array<Type^>(1);
   p[ 0 ] = String::typeid;
   myQueue->Formatter = gcnew XmlMessageFormatter( p );

   // Add an event handler for the ReceiveCompleted event.
   myQueue->ReceiveCompleted += gcnew ReceiveCompletedEventHandler( MyNewQueue::MyReceiveCompleted );

   // Begin the asynchronous receive operation.
   myQueue->BeginReceive();
   MyNewQueue::signal->WaitOne();

   // Do other work on the current thread.
   return 0;
}
using System;
using System.Messaging;
using System.Threading;

namespace MyProject
{
    /// <summary>
    /// Provides a container class for the example.
    /// </summary>
    public class MyNewQueue
    {
        // Define static class members.
        static ManualResetEvent signal = new ManualResetEvent(false);
        static int count = 0;

        //**************************************************
        // Provides an entry point into the application.
        //		
        // This example performs asynchronous receive
        // operation processing.
        //**************************************************

        public static void Main()
        {
            // Create an instance of MessageQueue. Set its formatter.
            MessageQueue myQueue = new MessageQueue(".\\myQueue");
            myQueue.Formatter = new XmlMessageFormatter(new Type[]
                {typeof(String)});

            // Add an event handler for the ReceiveCompleted event.
            myQueue.ReceiveCompleted +=
                new ReceiveCompletedEventHandler(MyReceiveCompleted);
            
            // Begin the asynchronous receive operation.
            myQueue.BeginReceive();

            signal.WaitOne();
            
            // Do other work on the current thread.

            return;
        }

        //***************************************************
        // Provides an event handler for the ReceiveCompleted
        // event.
        //***************************************************
        
        private static void MyReceiveCompleted(Object source,
            ReceiveCompletedEventArgs asyncResult)
        {
            try
            {
                // Connect to the queue.
                MessageQueue mq = (MessageQueue)source;

                // End the asynchronous receive operation.
                Message m = mq.EndReceive(asyncResult.AsyncResult);
                
                count += 1;
                if (count == 10)
                {
                    signal.Set();
                }

                // Restart the asynchronous receive operation.
                mq.BeginReceive();
            }
            catch(MessageQueueException)
            {
                // Handle sources of MessageQueueException.
            }
            
            // Handle other exceptions.
            
            return;
        }
    }
}
Imports System.Messaging
Imports System.Threading




' Provides a container class for the example.

Public Class MyNewQueue

        ' Define static class members.
        Private Shared signal As New ManualResetEvent(False)
        Private Shared count As Integer = 0



        ' Provides an entry point into the application.
        '		 
        ' This example performs asynchronous receive
        ' operation processing.


        Public Shared Sub Main()
            ' Create an instance of MessageQueue. Set its formatter.
            Dim myQueue As New MessageQueue(".\myQueue")
            myQueue.Formatter = New XmlMessageFormatter(New Type() _
                {GetType([String])})

            ' Add an event handler for the ReceiveCompleted event.
            AddHandler myQueue.ReceiveCompleted, AddressOf _
                MyReceiveCompleted

            ' Begin the asynchronous receive operation.
            myQueue.BeginReceive()

            signal.WaitOne()

            ' Do other work on the current thread.

            Return

        End Sub



        ' Provides an event handler for the ReceiveCompleted
        ' event.


        Private Shared Sub MyReceiveCompleted(ByVal [source] As _
            [Object], ByVal asyncResult As ReceiveCompletedEventArgs)

            Try
                ' Connect to the queue.
                Dim mq As MessageQueue = CType([source], MessageQueue)

                ' End the asynchronous receive operation.
                Dim m As Message = _
                    mq.EndReceive(asyncResult.AsyncResult)

                count += 1
                If count = 10 Then
                    signal.Set()
                End If

                ' Restart the asynchronous receive operation.
                mq.BeginReceive()

            Catch
                ' Handle sources of MessageQueueException.

                ' Handle other exceptions.

            End Try

            Return

        End Sub

End Class

Remarks

Quando o evento de ReceiveCompleted é gerado, EndReceive(IAsyncResult) conclui a operação que foi iniciada pela chamada BeginReceive.When the ReceiveCompleted event is raised, EndReceive(IAsyncResult) completes the operation that was initiated by the BeginReceive call. Para fazer isso, EndReceive(IAsyncResult) recebe a mensagem.To do so, EndReceive(IAsyncResult) receives the message.

BeginReceive pode especificar um tempo limite, o que faz com que o evento de ReceiveCompleted seja gerado se o tempo limite ocorrer antes que uma mensagem seja exibida na fila.BeginReceive can specify a time-out, which causes the ReceiveCompleted event to be raised if the time-out occurs before a message appears in the queue. Quando um tempo limite ocorre sem uma mensagem chegando na fila, uma chamada subsequente para EndReceive(IAsyncResult) gera uma exceção.When a time-out occurs without a message arriving in the queue, a subsequent call to EndReceive(IAsyncResult) throws an exception.

EndReceive(IAsyncResult) é usado para ler (removendo da fila) a mensagem que causou a geração do evento de ReceiveCompleted.EndReceive(IAsyncResult) is used to read (removing from the queue) the message that caused the ReceiveCompleted event to be raised.

Se quiser continuar a receber mensagens de forma assíncrona, você poderá chamar novamente BeginReceive depois de chamar EndReceive(IAsyncResult).If you want to continue to asynchronously receive messages, you can again call BeginReceive after calling EndReceive(IAsyncResult).

A tabela a seguir mostra se esse método está disponível em vários modos de grupo de trabalho.The following table shows whether this method is available in various Workgroup modes.

Modo de grupo de trabalhoWorkgroup mode DisponívelAvailable
Computador localLocal computer SimYes
Computador local e nome de formato diretoLocal computer and direct format name SimYes
Computador remotoRemote computer NãoNo
Computador remoto e nome de formato diretoRemote computer and direct format name SimYes

Applies to

See also