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MessageQueue.EndReceive Method

Completes the specified asynchronous receive operation.

Namespace:  System.Messaging
Assembly:  System.Messaging (in System.Messaging.dll)

public Message EndReceive(
	IAsyncResult asyncResult
)

Parameters

asyncResult
Type: System.IAsyncResult
The IAsyncResult that identifies the asynchronous receive operation to finish and from which to retrieve an end result.

Return Value

Type: System.Messaging.Message
The Message associated with the completed asynchronous operation.

ExceptionCondition
ArgumentNullException

The asyncResult parameter is null.

ArgumentException

The syntax of the asyncResult parameter is not valid.

MessageQueueException

An error occurred when accessing a Message Queuing method.

When the ReceiveCompleted event is raised, EndReceive(IAsyncResult) completes the operation that was initiated by the BeginReceive call. To do so, EndReceive(IAsyncResult) receives the message.

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. When a time-out occurs without a message arriving in the queue, a subsequent call to EndReceive(IAsyncResult) throws an exception.

EndReceive(IAsyncResult) is used to read (removing from the queue) the message that caused the ReceiveCompleted event to be raised.

If you want to continue to asynchronously receive messages, you can again call BeginReceive after calling EndReceive(IAsyncResult).

The following table shows whether this method is available in various Workgroup modes.

Workgroup mode

Available

Local computer

Yes

Local computer and direct format name

Yes

Remote computer

No

Remote computer and direct format name

Yes

The following code example chains asynchronous requests. It assumes there is a queue on the local computer called "myQueue". The Main function begins the asynchronous operation that is handled by the MyReceiveCompleted routine. MyReceiveCompleted processes the current message and begins a new asynchronous receive operation.


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; 
		}
	}
}


.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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