MSMQ和轮询接收消息？

Question

我有一个Windows 服务,可以进行一些图像转换.它可以在重命名任何文件(在特定文件夹中)时触发(即重命名文件观察者).工作得很好,直到我在该文件夹中转储(和重命名)大量图像.CPU红线等.

所以,我打算更改我的代码以使用MSMQ排队所有需要转换的文件.精细.每次重命名文件并触发文件监视器时,我都会向队列中添加一条新消息.KEWL.

问题是这个 - > 我如何从队列中一次抓取一条消息？

我是否需要制作一个每隔xxx秒轮询一次队列的计时器对象？或者有没有办法不断窥视队列中的第一个项目.一旦消息存在,提取它,处理它,然后继续(这意味着,继续偷看,直到世界爆炸).

我想知道我是否只需要在Receive方法周围放置一个while循环.Pseduo代码如下(在编辑#2中)......

任何人都有这方面的经验并有一些建议吗？

谢天谢地!

编辑:

如果WCF是要走的路,有人可以提供一些示例代码等吗？

编辑2:

这是我正在考虑的一些伪代码....

// Windows service start method.
protected override void OnStart(string[] args)
{
   // some initialisation stuf...

   // Start polling the queue.
   StartPollingMSMQ();

   // ....
}

private static void StartPollingMSMQ()
{
    // NOTE: This code should check if the queue exists, instead of just assuming it does.
    //       Left out for berevity.
    MessageQueue messageQueue = new MessageQueue(".\\Foo");

    while (true)
    {
        // This blocks/hangs here until a message is received.
        Message message = messageQueue.Receive(new TimeSpan(0, 0, 1));

        // Woot! we have something.. now process it...
        DoStuffWithMessage(message);

        // Now repeat for eva and eva and boomski...
    }
}

Answer 1

如果使用本地队列,则不需要WCF.

这是我的示例服务(来自Windows服务项目的服务clas)的样子:

using System.Messaging;
public partial class MQProcessTest1 : ServiceBase
{
    //a name of the queue
    private const string MqName = @".\Private$\test1";
    //define static local private queue
    private static MessageQueue _mq;
    //lazy local property through which we access queue (it initializes queue when needed)
    private static MessageQueue mq
    {
        get
        {
            if (_mq == null)
            {
                if (!MessageQueue.Exists(MqName))
                    MessageQueue.Create(MqName);
                _mq = new MessageQueue(MqName, QueueAccessMode.ReceiveAndAdmin);
                _mq.Formatter = new BinaryMessageFormatter();
            }
            return _mq;
        }
    }

    //constructor
    public MQProcessTest1()
    {
        InitializeComponent();
        //event to process received message 
        mq.ReceiveCompleted += new ReceiveCompletedEventHandler(mq_ReceiveCompleted);
    }

    //method to process message
    private void mq_ReceiveCompleted(object sender, ReceiveCompletedEventArgs e)
    {
        //queue that have received a message
        MessageQueue cmq = (MessageQueue)sender;
        try
        {
            //a message we have received (it is already removed from queue)
            Message msg = cmq.EndReceive(e.AsyncResult);
            //here you can process a message
        }
        catch
        {
        }
        //refresh queue just in case any changes occurred (optional)
        cmq.Refresh();
        //tell MessageQueue to receive next message when it arrives
        cmq.BeginReceive();
    }

    protected override void OnStart(string[] args)
    {
        //let start receive a message (when arrives)
        if (mq != null)
            mq.BeginReceive();
        //you can do any additional logic if mq == null
    }

    protected override void OnStop()
    {
        //close MessageQueue on service stop
        if (mq != null)
            mq.Close();
        return;
    }
}