创建Service Bus能够參照：

https://azure.microsoft.com/en-gb/documentation/articles/service-bus-dotnet-how-to-use-topics-subscriptions/

Azure Service Bus做广播和消息通知功能非常合适，而且能够订阅不同的Topic（不同的消息类型或不同的聊天室）。

1. 首先须要安装Azure Service Bus的nuget package：

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2. 建议安装Azure Service Explorer来查看Service bus中创建的Q或者Topic（本文主要介绍Topic）

https://code.msdn.microsoft.com/windowsazure/Service-Bus-Explorer-f2abca5a

非常好用。而且开源，能够学习。

3. 实现过程

3.1 首先创建1个Winform程序，拖两个button和两个Textbox。界面例如以下：

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3.2 创建1个类，叫ChatClient：

public class ChatClient

    {

        private string ConnStr

        {

            get

            {

                return CloudConfigurationManager.GetSetting("Microsoft.ServiceBus.ConnectionString");

            }

        }

        private const string topicName = "TestTopic";

        public OnMsgRecieved OnMsgRecieved;

        public void Subscribe(string subscriber)

        {

            var td = new TopicDescription(topicName)

            {

                MaxSizeInMegabytes = 5120,

                DefaultMessageTimeToLive = new TimeSpan(0, 1, 0)

            };

            // Create a new Topic with custom settings

            string connectionString =

                CloudConfigurationManager.GetSetting("Microsoft.ServiceBus.ConnectionString");

            var namespaceManager =

                NamespaceManager.CreateFromConnectionString(connectionString);

            if (!namespaceManager.TopicExists(topicName))

            {

                namespaceManager.CreateTopic(td);

            }

            if (!namespaceManager.SubscriptionExists(topicName, subscriber))

            {

                namespaceManager.CreateSubscription(topicName, subscriber);

            }

            SubscriptionClient Client = SubscriptionClient.CreateFromConnectionString

            (ConnStr, topicName, subscriber, ReceiveMode.PeekLock);

            // Configure the callback options

            OnMessageOptions options = new OnMessageOptions();

            options.AutoComplete = false;

            options.AutoRenewTimeout = TimeSpan.FromMinutes(1);

            Task.Run(() =>

            {

                Client.OnMessage((message) =>

                {

                    try

                    {

                        // Process message from subscription

                        OnMsgRecieved(string.Format("{0}:{1}",

                            message.Properties["name"], message.GetBody<string>()));

                    }

                    catch (Exception)

                    {

                        // Indicates a problem, unlock message in subscription

                        message.Abandon();

                    }

                }, options);

            });

        }

        private TopicClient _topicClient;

        public TopicClient TopicClient

        {

            get

            {

                if (_topicClient == null)

                {

                    _topicClient = TopicClient.CreateFromConnectionString(ConnStr, topicName);

                }

                return _topicClient;

            }

        }

        public void SendMsg(string name, string msg)

        {

            var message = new BrokeredMessage(msg);

            message.Properties["name"] = name;

            TopicClient.Send(message);

        }

    }

1. 代码包括了Subscribe和SendMsg两个方法，注意name用于标识client的。假设两个client给一样的名字，仅仅有client1个client能收到消息。

2. 我Hard Code了Topic名称，假设须要实现多种消息广播。给不同的名字就能够了

3. 这行代码：

SubscriptionClient Client = SubscriptionClient.CreateFromConnectionString

            (ConnStr, topicName, subscriber, ReceiveMode.PeekLock);

中的ReceiveMode包括两种：PeekLock和ReceiveAndDelete ，前者加锁拿消息放回，后者拿消息并删除。

4. TopicClient不必每次都创建。是支持多线程环境的。

5. 

var td = new TopicDescription(topicName)

            {

                MaxSizeInMegabytes = 5120,

                DefaultMessageTimeToLive = new TimeSpan(0, 1, 0)

            };

这里设置了消息的最大长度和默认生命周期，可依据场景进行配置。

Winform的UI逻辑代码相对简单：

 public partial class Form1 : Form

    {

        ChatClient cc = new ChatClient();

        public Form1()

        {

            InitializeComponent();

            cc.OnMsgRecieved = (msg) =>

            {

                SetText(msg);

            };

        }

        private void btnSend_Click(object sender, EventArgs e)

        {

            cc.SendMsg(txtName.Text, txtMsg.Text);

        }

        delegate void SetTextCallback(string text);

        private void SetText(string text)

        {

            if (txtResult.InvokeRequired)

            {

                var d = new SetTextCallback(SetText);

                Invoke(d, new object[] { text });

            }

            else

            {

                txtResult.Text += "\r\n" + text;

            }

        }

        private void btnSaveName_Click(object sender, EventArgs e)

        {

            cc.Subscribe(txtName.Text);

        }

    }

逻辑非常easy，点击SaveName。又一次订阅。点Send按钮，发送消息。

须要注意的就是跨线程訪问UI控件，这里你须要一个delegate。

实现截图：