Was this page helpful?
Your feedback about this content is important. Let us know what you think.
Additional feedback?
1500 characters remaining
BeginReceive Method

MessageQueue.BeginReceive Method

Initiates an asynchronous receive operation by telling Message Queuing to begin receiving a message and notify the event handler when finished.

Overload List

Initiates an asynchronous receive operation that has no time-out. The operation is not complete until a message becomes available in the queue.

[Visual Basic] Overloads Public Function BeginReceive() As IAsyncResult
[C#] public IAsyncResult BeginReceive();
[C++] public: IAsyncResult* BeginReceive();
[JScript] public function BeginReceive() : IAsyncResult;

Initiates an asynchronous receive operation that has a specified time-out. The operation is not complete until either a message becomes available in the queue or the time-out occurs.

[Visual Basic] Overloads Public Function BeginReceive(TimeSpan) As IAsyncResult
[C#] public IAsyncResult BeginReceive(TimeSpan);
[C++] public: IAsyncResult* BeginReceive(TimeSpan);
[JScript] public function BeginReceive(TimeSpan) : IAsyncResult;

Initiates an asynchronous receive operation that has a specified time-out and a specified state object, which provides associated information throughout the operation's lifetime. The operation is not complete until either a message becomes available in the queue or the time-out occurs.

[Visual Basic] Overloads Public Function BeginReceive(TimeSpan, Object) As IAsyncResult
[C#] public IAsyncResult BeginReceive(TimeSpan, object);
[C++] public: IAsyncResult* BeginReceive(TimeSpan, Object*);
[JScript] public function BeginReceive(TimeSpan, Object) : IAsyncResult;

Initiates an asynchronous receive operation that has a specified time-out and a specified state object, which provides associated information throughout the operation's lifetime. This overload receives notification, through a callback, of the identity of the event handler for the operation. The operation is not complete until either a message becomes available in the queue or the time-out occurs.

[Visual Basic] Overloads Public Function BeginReceive(TimeSpan, Object, AsyncCallback) As IAsyncResult
[C#] public IAsyncResult BeginReceive(TimeSpan, object, AsyncCallback);
[C++] public: IAsyncResult* BeginReceive(TimeSpan, Object*, AsyncCallback*);
[JScript] public function BeginReceive(TimeSpan, Object, AsyncCallback) : IAsyncResult;

Example

[Visual Basic, C#, C++] The following 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.

[Visual Basic, C#, C++] Note   This example shows how to use one of the overloaded versions of BeginReceive. For other examples that might be available, see the individual overload topics.
[Visual Basic] 
Imports System
Imports System.Messaging
Imports System.Threading

Namespace MyProject

    '/ <summary>
    '/ Provides a container class for the example.
    '/ </summary>
    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 'Main


        '***************************************************
        ' 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 'MyReceiveCompleted

    End Class 'MyNewQueue
End Namespace 'MyProject

[C#] 
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; 
        }
    }
}

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

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

__gc class MyNewQueue 
{
public:
    // Define static class members.
    static ManualResetEvent* signal = new ManualResetEvent(false);
    static int count = 0;

    // Provides an event handler for the ReceiveCompleted
    // event.

public:
    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 = new MessageQueue(S".\\myQueue");

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

    // Add an event handler for the ReceiveCompleted event.
    myQueue->ReceiveCompleted += new ReceiveCompletedEventHandler(0, MyNewQueue::MyReceiveCompleted);

    // Begin the asynchronous receive operation.
    myQueue->BeginReceive();

    MyNewQueue::signal->WaitOne();

    // Do other work on the current thread.

    return 0;
}

[Visual Basic, C#, C++] The following example queues asynchronous requests. The call to BeginReceive uses the AsyncWaitHandle in its return value. The Main routine waits for all asynchronous operations to be completed before exiting.

[Visual Basic] 
Imports System
Imports System.Messaging
Imports System.Threading

Namespace MyProject

    '/ <summary>
    '/ Provides a container class for the example.
    '/ </summary>
    Public Class MyNewQueue

        '**************************************************
        ' 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

            ' Define wait handles for multiple operations.
            Dim waitHandleArray(10) As WaitHandle

            Dim i As Integer
            For i = 0 To 9
                ' Begin asynchronous operations.
                waitHandleArray(i) = _
                    myQueue.BeginReceive().AsyncWaitHandle
            Next i

            ' Specify to wait for all operations to return.
            WaitHandle.WaitAll(waitHandleArray)

            Return

        End Sub 'Main


        '***************************************************
        ' 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)

                ' Process the message here.
                Console.WriteLine("Message received.")

            Catch

                ' Handle sources of MessageQueueException.

                ' Handle other exceptions.

            End Try

            Return

        End Sub 'MyReceiveCompleted

    End Class 'MyNewQueue
End Namespace 'MyProject

[C#] 
using System;
using System.Messaging;
using System.Threading;

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

        //**************************************************
        // 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);
            
            // Define wait handles for multiple operations.
            WaitHandle[] waitHandleArray = new WaitHandle[10];
            for(int i=0; i<10; i++)
            {
                // Begin asynchronous operations.
                waitHandleArray[i] = 
                    myQueue.BeginReceive().AsyncWaitHandle;
            }

            // Specify to wait for all operations to return.
            WaitHandle.WaitAll(waitHandleArray);
         
            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);
        
                // Process the message here.
                Console.WriteLine("Message received.");

            }
            catch(MessageQueueException)
            {
                // Handle sources of MessageQueueException.
            }
            
            // Handle other exceptions.
            
            return; 
        }
    }
}

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

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

__gc class MyNewQueue 
{
    // Provides an event handler for the ReceiveCompleted
    // event.

public:
    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);

            // Process the message here.
            Console::WriteLine(S"Message received.");

        }
        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 = new MessageQueue(S".\\myQueue");

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

    // Add an event handler for the ReceiveCompleted event.
    myQueue->ReceiveCompleted += new ReceiveCompletedEventHandler(0, MyNewQueue::MyReceiveCompleted);

    // Define wait handles for multiple operations.
    WaitHandle* waitHandleArray[] = new WaitHandle*[10];
    for (int i=0; i<10; i++) 
    {
        // Begin asynchronous operations.
        waitHandleArray->Item[i] = myQueue->BeginReceive()->AsyncWaitHandle;
    }

    // Specify to wait for all operations to return.
    WaitHandle::WaitAll(waitHandleArray);

    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.

See Also

MessageQueue Class | MessageQueue Members | System.Messaging Namespace

Show:
© 2015 Microsoft