MessageQueueListener queueListener = new MessageQueueListener(sourceQueuePath, 4 );
queueListener.MessageReceived = new MessageReceivedEventHandler(queueListener MessageReceived);
queueListener.ProcessingError += new ProcessingErrorEventHandler(queueListener ProcessingError);
queueListener.Start();

using System;
using System.Collections;
using System.Messaging;
using System.Threading;

namespace newtelligence.EnterpriseTools.Msmq
{
    /// <summary>
    /// Event argument class for the MessageQueueListener.MessageReceived unicast event
    /// </summary>
    public class MessageReceivedEventArgs : EventArgs
    {
        private Message receivedMessage;

        /// <summary>
        /// Constructor
        /// </summary>
        /// <param name="receivedMessage">A message</param>
        public MessageReceivedEventArgs( Message receivedMessage )
        {
           this.receivedMessage = receivedMessage;
        }

        /// <summary>
        /// Received message
        /// </summary>
        public Message ReceivedMessage
        {
            get
            {
                return receivedMessage;
            }
        }
    }

    /// <summary>
    /// Event argument class for the MessageQueueListener.ProcessingError event
    /// </summary>
    public class ProcessingErrorEventArgs : EventArgs
    {
        /// <summary>
        ///
        /// </summary>
        private Exception exception;

        /// <summary>
        /// Constructor
        /// </summary>
        /// <param name="exception">An exception</param>
        public ProcessingErrorEventArgs( Exception exception )
        {
            this.exception = exception;
        }

        /// <summary>
        /// Intercepted exception
        /// </summary>
        public Exception Exception
        {
            get
            {
                return exception;
            }
        }
    }

    /// <summary>
    /// Delegate for the MessageQueueListener.MessageReceived unicast event
    /// </summary>
    public delegate void MessageReceivedEventHandler( object sender, MessageReceivedEventArgs ea );
    /// <summary>
    /// Delegate for the MessageQueueListener.ProcessingError event
    /// </summary>
    public delegate void ProcessingErrorEventHandler( object sender, ProcessingErrorEventArgs ea );
   
    /// <summary>
    /// This class implements a multi-threaded message queue listener
    /// </summary>
    public class MessageQueueListener
    {
        protected Guid instanceId = Guid.NewGuid();
        protected Thread[] listenerThreads;
        protected string queueName=null;
        protected int numThreads=1;
        protected ThreadPriority priority=ThreadPriority.Normal;
        protected ManualResetEvent continueInterrupt = new ManualResetEvent(true);
        protected ManualResetEvent pauseInterrupt = new ManualResetEvent(false);
        protected ManualResetEvent stopInterrupt = new ManualResetEvent(false);
        protected int peekTimeout = 5;
        protected MessageReceivedEventHandler messageReceived;
        protected int refCount = 0;
       
        /// <summary>
        /// Initializes a new instance of the MessageQueueListener class
        /// </summary>
        /// <param name="queueName">Message name where listener waits messages</param>
        public MessageQueueListener(string queueName)
        {
            queueName = queueName;
            Initialize();
        }

        /// <summary>
        /// Initializes a new instance of the MessageQueueListener class
        /// </summary>
        /// <param name="queueName">Name of the queue to listen on</param>
        /// <param name="numThreads">Number of threads to run the listener on</param>
        public MessageQueueListener(string queueName, int numThreads)
        {
            queueName = queueName;
            numThreads = numThreads;
            Initialize();
        }


        /// <summary>
        /// Initializes a new instance of the MessageQueueListener class
        /// </summary>
        /// <param name="queueName">Name of the queue to listen on</param>
        /// <param name="numThreads">Number of threads run the listener on</param>
        /// <param name="priority">Thread priority</param>
        public MessageQueueListener(string queueName, int numThreads, ThreadPriority priority)
        {
            queueName = queueName;
            numThreads = numThreads;
            priority = priority;
            Initialize();
        }


        /// <summary>
        /// Adds a reference to the reference counter.
        /// </summary>
        /// <returns>Current reference count</returns>
        public int AddReference()
        {
            return ++ refCount;
        }

        /// <summary>
        /// Releases a reference from the reference counter.
        /// </summary>
        /// <returns>Current reference count</returns>
        /// <remarks>If the reference counter drops to or below zero, the listener is stopped.</remarks>
        public int ReleaseReference()
        {
            if ( -- refCount <= 0 )
            {
                Stop();
            }
            return refCount;
        }

        /// <summary>
        /// Initializes the MessageQueueListener
        /// </summary>
        protected virtual void Initialize()
        {
            listenerThreads = new Thread[ numThreads];
        }

        /// <summary>
        /// Unicast event that is raised when a message has been received
        /// </summary>
        public MessageReceivedEventHandler MessageReceived
        {
            get
            {
                return messageReceived;
            }
            set
            {
                if ( messageReceived == value)
                    return;
                 messageReceived = value;
            }
        }

        /// <summary>
        /// Multicast event that is raised when an exception occurs during processing.
        /// </summary>
        public event ProcessingErrorEventHandler ProcessingError;

        /// <summary>
        /// Raises the ProcessingError event
        /// </summary>
        /// <param name="pea"></param>
        protected void OnProcessingError( ProcessingErrorEventArgs pea )
        {
            if (ProcessingError != null )
            {
                ProcessingError( this, pea );
            }
        }

        /// <summary>
        /// Starts the message queue listener. If the threads are already running,
        /// Start() does nothing.
        /// </summary>
        public void Start()
        {
            for(int i=0;i< numThreads;i++)
            {
                if ( listenerThreads[i] == null )
                {
                    Thread thread = new Thread(new ThreadStart(this.ReceiveLoop));
                    thread.Name = String.Format("{0}:{1}:{2}",i, instanceId,GetType().Name);
                    thread.IsBackground = true;
                    thread.Priority = priority;
                    listenerThreads[i] = thread;
                    thread.Start();
                }
            }
        }

        /// <summary>
        /// Set listener state in stop
        /// </summary>
        public void Stop()
        {
            Resume();
            stopInterrupt.Set();
            for(int i=0;i< numThreads;i++)
            {
                listenerThreads[i].Join();
                listenerThreads[i] = null;
            }
        }

        /// <summary>
        /// Set listener state to "paused".
        /// </summary>
        /// <remarks>
        /// Setting the listener ito the "paused" state will not suspend processing
        /// immediately. All messages that are currently being processed will be
        /// processed, but no new messages are being dequeued.
        /// </remarks>
        public void Pause()
        {
            continueInterrupt.Reset();
            pauseInterrupt.Set();                            
        }

        /// <summary>
        /// Set listener state to "resume". This will resume the listener from
        /// the "paused" state.
        /// </summary>
        public void Resume()
        {
            pauseInterrupt.Reset();
            continueInterrupt.Set();           
        }

        /// <summary>
        /// Gets a value indicating whether the listener is paused.
        /// </summary>
        public bool IsPaused
        {
            get
            {
                return pauseInterrupt.WaitOne(TimeSpan.Zero,false);
            }
        }

        /// <summary>
        /// Gets a value indicating whether the listener is paused.
        /// </summary>
        public bool IsStopping
        {
            get
            {
                return stopInterrupt.WaitOne(TimeSpan.Zero,false);
            }
        }


        /// <summary>
        /// This is the thread entry point for the main receive loop.
        /// </summary>
        protected virtual void ReceiveLoop()
        {
            using (MessageQueue sourceQueue = new MessageQueue( queueName, false ))
            {
                bool isTransactional = sourceQueue.Transactional;
                sourceQueue.MessageReadPropertyFilter.SetAll();

                while ( !IsStopping )
                {
                    // if the continue interrupt is not set, we will hang here
                    // until it is set again (resuming)
                    WaitHandle.WaitAny(new WaitHandle[]{ continueInterrupt, stopInterrupt});

                    try
                    {
                        //peek on the queue and wait for a message becoming available
                        IAsyncResult asynchResult = sourceQueue.BeginPeek(TimeSpan.FromSeconds( peekTimeout),null,null);
                        int firedWaitHandle = WaitHandle.WaitAny(new WaitHandle[]{asynchResult.AsyncWaitHandle, pauseInterrupt, stopInterrupt});
                        if ( firedWaitHandle == 0 )
                        {
                            sourceQueue.EndPeek(asynchResult);
                            Message receivedMessage = sourceQueue.Receive( TimeSpan.FromSeconds(0),
                                isTransactional?MessageQueueTransactionType.Single:MessageQueueTransactionType.None );
                          
                            try
                            {
                                messageReceived(this,new MessageReceivedEventArgs(receivedMessage));                       
                            }
                            finally
                            {
                                receivedMessage.Dispose();
                            }
                        }
                        else if ( firedWaitHandle == 1 )
                        {
                            // Pausing. Clean up the asynchronous Peek operation
                            // (we'll assume that we have time for that) and then go
                            // back to the top of the loop where we'll hang on the
                            // continueInterrupt.
                            sourceQueue.EndPeek(asynchResult);
                        }
                        else
                        {
                            // stopping. Skip the EndPeek() and exit the thread immediately.
                            return;
                        }
                    }
                    catch(MessageQueueException ex)
                    {
                        if ( ex.MessageQueueErrorCode != MessageQueueErrorCode.IOTimeout  )
                        {
                            break;
                        }
                    }
                    catch( Exception ex )
                    {
                        // absorb all other exceptions and surface them from he listener
                        // using the ProcessingError event.
                        OnProcessingError( new ProcessingErrorEventArgs(ex));
                    }
                }
            }
        }
    }
}