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MessageQueue.Receive Method (TimeSpan, MessageQueueTransaction)

.NET Framework 1.1

Receives the first message available in the transactional queue referenced by the MessageQueue and waits until either a message is available in the queue, or the time-out expires.

[Visual Basic]
Overloads Public Function Receive( _
   ByVal timeout As TimeSpan, _
   ByVal transaction As MessageQueueTransaction _
) As Message
[C#]
public Message Receive(
 TimeSpan timeout,
 MessageQueueTransaction transaction
);
[C++]
public: Message* Receive(
 TimeSpan timeout,
 MessageQueueTransaction* transaction
);
[JScript]
public function Receive(
   timeout : TimeSpan,
 transaction : MessageQueueTransaction
) : Message;

Parameters

timeout
A TimeSpan that indicates the time to wait until a new message is available for inspection.
transaction
The MessageQueueTransaction object.

Return Value

A Message that references the first message available in the queue.

Exceptions

Exception Type Condition
ArgumentException The value specified for the timeout parameter is invalid, possibly timeout is less than TimeSpan.Zero or greater than TimeSpan.MaxValue.
MessageQueueException A message did not arrive in the queue before the time-out expired.

-or-

The queue is non-transactional.

-or-

An error occurred when accessing a Message Queuing API.

Remarks

Use this overload to receive a message from a transactional queue using the internal transaction context defined by the transaction parameter, and return within a specified period of time if there are no 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. The thread will be blocked for the given period of time, or indefinitely if you specified the value InfiniteTimeout for the timeout parameter. If the application processing should continue without waiting for a 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 + direct format name Yes
Remote computer No
Remote computer + direct format name Yes

Example

[Visual Basic] 
Imports System
Imports 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 Shared Sub Main()

            ' Create a new instance of the class.
            Dim myNewQueue As New MyNewQueue()

            ' Send a message to a queue.
            myNewQueue.SendMessageTransactional()

            ' Receive a message from a queue.
            myNewQueue.ReceiveMessageTransactional()

            Return

        End Sub 'Main


        '**************************************************
        ' Sends a message to a transactional queue.
        '**************************************************

        Public Sub SendMessageTransactional()

            ' Connect to a queue on the local computer.
            Dim myQueue As New MessageQueue(".\myTransactionalQueue")

            ' Send a message to the queue.
            If myQueue.Transactional = True Then

                myQueue.Send("My Message Data.", New _
                    MessageQueueTransaction())

            End If

            Return

        End Sub 'SendMessageTransactional


        '**************************************************
        ' Receives a message from the transactional queue.
        '**************************************************

        Public Sub ReceiveMessageTransactional()

            ' Connect to a transactional queue on the local computer.
            Dim myQueue As New MessageQueue(".\myTransactionalQueue")

            ' Set the formatter.
            myQueue.Formatter = New XmlMessageFormatter(New Type() _
                {GetType([String])})

            ' Create a transaction.
            Dim myTransaction As New MessageQueueTransaction()

            Try

                ' Begin the transaction.
                myTransaction.Begin()

                ' Receive the message. 
                ' Wait five seconds for a message to arrive. 
                Dim myMessage As Message = myQueue.Receive(New _
                    TimeSpan(0, 0, 5), myTransaction)
                Dim myOrder As [String] = CType(myMessage.Body, _
                    [String])

                ' Display message information.
                Console.WriteLine(myOrder)

                ' Commit the transaction.
                myTransaction.Commit()


            Catch e As MessageQueueException

                ' Handle nontransactional queues.
                If e.MessageQueueErrorCode = _
                    MessageQueueErrorCode.TransactionUsage Then

                    Console.WriteLine("Queue is not transactional.")

                Else
                    ' Handle no message arriving in the queue.
                    If e.MessageQueueErrorCode = _
                        MessageQueueErrorCode.IOTimeout Then

                        Console.WriteLine("No message in queue.")

                    End If
                End If

                ' 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.

            End Try

            Return

        End Sub 'ReceiveMessageTransactional

    End Class 'MyNewQueue
End Namespace 'MyProject

[C#] 
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 transactional 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)
            {
                myQueue.Send("My Message Data.", new 
                    MessageQueueTransaction());
            }

            return;
        }


        //**************************************************
        // Receives a message from the transactional queue.
        //**************************************************
        
        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. 
                // Wait five seconds for a message to arrive. 
                Message myMessage =    myQueue.Receive(new 
                    TimeSpan(0,0,5), 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.");
                }

                // Handle no message arriving in the queue.
                else if (e.MessageQueueErrorCode == 
                    MessageQueueErrorCode.IOTimeout)
                {
                    Console.WriteLine("No message in queue.");
                }
                
                // Else catch other sources of MessageQueueException.

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

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

            return;
        }
    }
}

[C++] 
#using <mscorlib.dll>
#using <system.dll>
#using <system.messaging.dll>

using namespace System;
using namespace System::Messaging;

/// <summary>
/// Provides a container class for the example.
/// </summary>
__gc class MyNewQueue 
{
    //*************************************************
    // Sends a message to a transactional queue.
    //*************************************************
public:
    void SendMessageTransactional() 
    {
        // Connect to a queue on the local computer.
        MessageQueue* myQueue = new MessageQueue(S".\\myTransactionalQueue");

        // Send a message to the queue.
        if (myQueue->Transactional == true) 
        {
            myQueue->Send(S"My Message Data.", new MessageQueueTransaction());
        }

        return;
    }

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

        // Set the formatter.
        Type* p __gc[] = new Type* __gc[1];
        p[0] = __typeof(String);
        myQueue->Formatter = new XmlMessageFormatter( p );

        // Create a transaction.
        MessageQueueTransaction* myTransaction = new MessageQueueTransaction();

        try 
        {
            // Begin the transaction.
            myTransaction->Begin();

            // Receive the message. 
            // Wait five seconds for a message to arrive. 
            Message* myMessage = myQueue->Receive(TimeSpan(0, 0, 5), myTransaction); 

            String* myOrder = static_cast<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(S"Queue is not transactional.");
            }

            // Handle no message arriving in the queue.
            else if (e->MessageQueueErrorCode == 
                MessageQueueErrorCode::IOTimeout) 
            {
                Console::WriteLine(S"No message in queue.");
            }

            // Else catch other sources of MessageQueueException.

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

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

        return;
    }
};

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

int 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 0;
}

[JScript] No example is available for JScript. To view a Visual Basic, C#, or C++ example, click the Language Filter button Language Filter in the upper-left corner of the page.

Requirements

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family

.NET Framework Security: 

See Also

MessageQueue Class | MessageQueue Members | System.Messaging Namespace | MessageQueue.Receive Overload List | MessageQueueTransaction | Transactional | InfiniteTimeout | ReceiveById | ReceiveByCorrelationId | Peek | BeginReceive

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