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MessageQueue.Receive Method (MessageQueueTransaction)

Receives the first message available in the transactional queue referenced by the MessageQueue. This call is synchronous, and blocks the current thread of execution until a message is available.

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

public Message Receive(
	MessageQueueTransaction transaction
)

Return Value

Type: System.Messaging.Message
A Message that references the first message available in the queue.

ExceptionCondition
MessageQueueException

An error occurred when accessing a Message Queuing method.

-or-

The queue is non-transactional.

Use this overload to receive a message from a transactional queue using the internal transaction context defined by the transaction parameter, or wait until there are messages in the queue.

The Receive method allows for the synchronous reading of a message, thereby removing it from the queue. Subsequent calls to Receive will return the messages that follow in the queue.

Because this method is called on a transactional queue, the message that is received would be returned to the queue if the transaction is aborted. The message is not permanently removed from the queue until the transaction is committed.

To read the first message in a queue without removing it from the queue, use the Peek method. The Peek method always returns the first message in the queue, so subsequent calls to the method return the same message unless a higher priority message arrives in the queue. There is no transaction context associated with a message returned by a call to Peek. Because Peek does not remove any messages in the queue, there would be nothing to roll back by a call to Abort.

Use a call to Receive when it is acceptable for the current thread to be blocked while it waits for a message to arrive in the queue. Because this overload of the Receive method specifies an infinite time-out, the application might wait indefinitely. If the application processing should continue without waiting for the message, consider using the asynchronous method, BeginReceive.

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 connects to a transactional queue on the local computer and sends a message to the queue. It then receives the message that contains an order. If it encounters a non-transactional queue, it will throw and exception and rollback the transaction.

using System;
using System.Messaging;

namespace MyProject
{

    /// <summary> 
    /// Provides a container class for the example. 
    /// </summary> 
    public class MyNewQueue
    {

        //************************************************** 
        // Provides an entry point into the application. 
        //  
        // This example sends and receives a message from 
        // a transactional queue. 
        //************************************************** 

        public static void Main()
        {
            // Create a new instance of the class.
            MyNewQueue myNewQueue = new MyNewQueue();

            // Send a message to a queue.
            myNewQueue.SendMessageTransactional();

            // Receive a message from a queue.
            myNewQueue.ReceiveMessageTransactional();

            return;
        }


        //************************************************** 
        // Sends a message to a queue. 
        //************************************************** 
		
        public void SendMessageTransactional()
        {
						
            // Connect to a queue on the local computer.
            MessageQueue myQueue = new 
                MessageQueue(".\\myTransactionalQueue");

            // Send a message to the queue. 
            if (myQueue.Transactional == true)
            {
                // Create a transaction.
                MessageQueueTransaction myTransaction = new 
                    MessageQueueTransaction();

                // Begin the transaction.
                myTransaction.Begin();

                // Send the message.
                myQueue.Send("My Message Data.", myTransaction);

                // Commit the transaction.
                myTransaction.Commit();
            }

            return;
        }


        //************************************************** 
        // Receives a message containing an Order. 
        //************************************************** 
		
        public   void ReceiveMessageTransactional()
        {
            // Connect to a transactional queue on the local computer.
            MessageQueue myQueue = new 
                MessageQueue(".\\myTransactionalQueue");

            // Set the formatter.
            myQueue.Formatter = new XmlMessageFormatter(new Type[]
                {typeof(String)});
			
            // Create a transaction.
            MessageQueueTransaction myTransaction = new 
                MessageQueueTransaction();

            try
            {
                // Begin the transaction.
                myTransaction.Begin();
				
                // Receive the message. 
                Message myMessage =	myQueue.Receive(myTransaction); 
                String myOrder = (String)myMessage.Body;

                // Display message information.
                Console.WriteLine(myOrder);

                // Commit the transaction.
                myTransaction.Commit();

            }
			
            catch (MessageQueueException e)
            {
                // Handle nontransactional queues. 
                if (e.MessageQueueErrorCode == 
                    MessageQueueErrorCode.TransactionUsage)
                { 
                    Console.WriteLine("Queue is not transactional.");
                }
				
                // Else catch other sources of a MessageQueueException. 

                // Roll back the transaction.
                myTransaction.Abort();
            }

            // Catch other exceptions as necessary, such as  
            // InvalidOperationException, thrown when the formatter  
            // cannot deserialize the message. 

            return;
        }
    }
}

.NET Framework

Supported in: 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

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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