Windows服务仅在服务启动时才第一次收到MSMQ消息

Question

I am first time working with both windows service and MSMQ. I am trying to read messages from queue. When I start my windows service, i am receiving only first message and next message not able to read, service is still running. if I restart the service It is reading first message from the queue. Please let me know how to fix this issue.

This is my code on start of my service:

protected override void OnStart(string[] args)
    {

        MessageQueue msMq = null;
        JobModel j = new JobModel();
        msMq = new MessageQueue(queueRequestName);
        try
        {            
            if (msMq != null)
            {                    
                msMq.Formatter = new XmlMessageFormatter(new Type[] { typeof(JobModel) });
                var message = (JobModel)msMq.BeginReceive();        

            }
        }

        catch (MessageQueueException ee)
        {
            Console.Write(ee.ToString());
        }
        catch (Exception eee)
        {
            Console.Write(eee.ToString());
        }
        finally
        {
            msMq.Close();
        }
    }

Answer 1

Just a guess, but I think you shouldn't close the queue:

//keep your queue object in the service scope
//you might need more 
MessageQueue msMq = null;
protected override void OnStart(string[] args)
{   
    JobModel j = new JobModel();
    msMq = new MessageQueue(queueRequestName);
    try
    {            
        if (msMq != null)
        {                    
            msMq.Formatter = new XmlMessageFormatter(new Type[] { typeof(JobModel) });
            var message = (JobModel)msMq.BeginReceive(); 
        }
    }

    catch (MessageQueueException ee)
    {
        Console.Write(ee.ToString());
    }
    catch (Exception eee)
    {
        Console.Write(eee.ToString());
    }
}

//close when you stop
protected override OnStop() //signature might be differnt
{
    msMq.Close();
}

Answer 2

Have you tried adding an event handler and attaching it to the ReceiveCompleted event, as shown in MessageQueue.BeginReceive ?

protected override void OnStart(string[] args)
{

    MessageQueue msMq = null;
    JobModel j = new JobModel();
    msMq = new MessageQueue(queueRequestName);
    msMq.ReceiveCompleted += ReceiveCompletedEventHandler(MyMsMqEventHandler)
    try
    {            
        if (msMq != null)
        {                    
            msMq.Formatter = new XmlMessageFormatter(new Type[] { typeof(JobModel) });
            var message = (JobModel)msMq.BeginReceive();        

        }
    }

    catch (MessageQueueException ee)
    {
        Console.Write(ee.ToString());
    }
    catch (Exception eee)
    {
        Console.Write(eee.ToString());
    }
}

public static void MyMsMqEventHandler(object src, ReceiveCompletedEventHandler handler)
{
     var msMq = (MessageQueue)src;
     var msg = msMq.EndReceive(handler.AsyncResult);
     Console.WriteLine((string)msMq.Body);
     msMq.BeginReceive();
}