处理我刚刚使用 ActiveMQ 和 C# 发送的消息

Question

我是使用 ActiveMQ 与 C# 的初学者。我创建了一个简单的窗口窗体，其中包含一个按钮和一个标签。当我单击按钮时，我会向队列发送一条消息，并且标签会使用我刚刚发送的消息进行初始化。当然，我可以直接初始化我的标签，但我希望我的表单使用队列中的消息来更新我的标签。

问题是我无法以相同的形式处理消息来更新我的标签。我的消费者代码根本没有被调用，但它是在我的表单的 Load 事件中初始化的。 这是代码

    protected override void OnLoad(EventArgs e)
    {
        base.OnLoad(e);
        InitializeHandlerAMQ();
    }

    private void InitializeHandlerAMQ()
    {
        Tchat tchat = null;
        IDestination dest = _session.GetQueue(QUEUE_DESTINATION);
        using(IMessageConsumer consumer = _session.CreateConsumer(dest))
        {
            IMessage message;
            while((message = consumer.Receive(TimeSpan.FromMilliseconds(2000))) != null)
            {
                var objectMessage = message as IObjectMessage;
                if(objectMessage != null)
                {
                    tchat = objectMessage.Body as Tchat;
                    if (tchat != null)
                    {
                        textBox2.Text += string.Format("{0}{1}", tchat.Message, Environment.NewLine);
                    }
                }
            }
        }
    }

如果我关闭 Windows 窗体并重新启动它，那么我的标签已很好更新，但我不想关闭它并重新打开它。

你们有什么想法吗？

Answer 1

尝试创建一个带有这样的事件委托的类。

订阅者类别

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Apache.NMS;
using Apache.NMS.ActiveMQ;
using Apache.NMS.ActiveMQ.Commands;

namespace Utilities
{
    public delegate void QMessageReceivedDelegate(string message);
    public class MyQueueSubscriber : IDisposable
    {
        private readonly string topicName = null;
        private readonly IConnectionFactory connectionFactory;
        private readonly IConnection connection;
        private readonly ISession session;
        private readonly IMessageConsumer consumer;
        private bool isDisposed = false;
        public event QMessageReceivedDelegate OnMessageReceived;

        public MyQueueSubscriber(string queueName, string brokerUri, string clientId)
        {
            this.topicName = queueName;
            this.connectionFactory = new ConnectionFactory(brokerUri);
            this.connection = this.connectionFactory.CreateConnection();
            this.connection.ClientId = clientId;
            this.connection.Start();
            this.session = connection.CreateSession();
            ActiveMQQueue topic = new ActiveMQQueue(queueName);
            //this.consumer = this.session.CreateDurableConsumer(topic, consumerId, "2 > 1", false);
            this.consumer = this.session.CreateConsumer(topic, "2 > 1");
            this.consumer.Listener += new MessageListener(OnMessage);

        }

        public void OnMessage(IMessage message)
        {
            ITextMessage textMessage = message as ITextMessage;
            if (this.OnMessageReceived != null)
            {
                this.OnMessageReceived(textMessage.Text);
            }
        }

        #region IDisposable Members

        public void Dispose()
        {
            if (!this.isDisposed)
            {
                this.consumer.Dispose();
                this.session.Dispose();
                this.connection.Dispose();
                this.isDisposed = true;
            }
        }

        #endregion

    }
}

Winforms
在您的 Windows 窗体中像这样订阅队列

    MyQueueSubscriber QueueSubscriber = new MyQueueSubscriber(QueueName, ActiveMQHost, QueueClientId);
    QueueSubscriber.OnMessageReceived += new QMessageReceivedDelegate(QueueSubscriber_OnMessageReceived);

static void QueueSubscriber_OnMessageReceived(string message)
{
        SetText(message);
}

    private void SetText(string text)
    {
        // InvokeRequired required compares the thread ID of the
        // calling thread to the thread ID of the creating thread.
        // If these threads are different, it returns true.
        if (this.textBox1.InvokeRequired)
        {   
            SetTextCallback d = new SetTextCallback(SetText);
            this.Invoke(d, new object[] { text });
        }
        else
        {
            this.labelname.value = text;
        }
    }

资源：
不幸的是，没有那么多资源来教授 C# 和 C#。 ActiveMQ。尝试使用 http://activemq.apache.org/nms/ 因为这非常好。

尝试查看 http://www.codersource.net/MicrosoftNet/CAdvanced/ 中的一篇小文章在CusingActiveMQ.aspx 中发布订阅。免责声明：这是我的网站，文章是我写的。抱歉，自我宣传。但我觉得这与主题相关。