MessageQueue.EndReceive(IAsyncResult) 方法

定義

命名空間:

System.Messaging

組件:

System.Messaging.dll

完成指定的非同步接收作業。

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

參數

asyncResult

IAsyncResult

IAsyncResult，識別要完成的非同步接收作業，並要從其中擷取最終結果。

傳回

Message

與完成的非同步作業相關的 Message。

例外狀況

ArgumentNullException

asyncResult 參數為 null。

ArgumentException

asyncResult 參數的語法無效。

MessageQueueException

存取訊息佇列方法時發生錯誤。

範例

下列程式代碼範例會鏈結異步要求。 它假設本機電腦上有一個名為 「myQueue」 的佇列。 函 Main 式會開始由例程處理的 MyReceiveCompleted 異步操作。 MyReceiveCompleted 會處理目前的訊息，並開始新的異步接收作業。

#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

備註

ReceiveCompleted引發事件時，EndReceive(IAsyncResult)完成呼叫所起始的BeginReceive作業。 若要這樣做， EndReceive(IAsyncResult) 請接收訊息。

BeginReceive 可以指定逾時，這會導致 ReceiveCompleted 在訊息出現在佇列中的訊息之前引發事件。 當逾時發生時，沒有訊息抵達佇列時，後續呼叫 會 EndReceive(IAsyncResult) 擲回例外狀況。

EndReceive(IAsyncResult) 用來讀取 (從佇列中移除) 導致 ReceiveCompleted 引發事件的訊息。

如果您要繼續以異步方式接收訊息，您可以在呼叫 之後再次呼叫 BeginReceiveEndReceive(IAsyncResult)。

下表顯示這個方法是否可在各種工作組模式中使用。

工作組模式	可用
本機電腦	是
本機計算機和直接格式名稱	是
遠端電腦	否
遠端電腦和直接格式名稱	是

另請參閱

• BeginReceive()
• ReceiveCompleted