一、引言
fanout型別的Exchange，路由規則非常簡單：它會把所有發送到該Exchange的訊息，路由到所有與它系結的Queue中，假設有一個聊天室，各個客戶端都訂閱在同一fanout exchange type，那每個客戶端發送出來的訊息，所有的客戶端都能收到，因為大家都訂閱了，此時，只需要簡單地限制一下，只有是與我有關的訊息，才在聊天界面上顯示，這樣，即可達到相互通訊的效果，
二、示例
2.1、環境準備
本示例使用EasyNetQ來實作，請先在NuGet上安裝，
2.2、物體類
新建一個物體類MessageBody：
public class MessageBody { public string FromUserId { get; set; } public string Message { get; set; } public string ToUserId { get; set; } }
2.3、主表單
新建一個ChatMain表單：
代碼如下：
public partial class ChatMain : Form { public ChatMain() { InitializeComponent(); } /// <summary> /// 客戶端 A /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void Button1_Click(object sender, EventArgs e) { ChatWith chatWith = new ChatWith(currentUserId: "UserA") { StartPosition = FormStartPosition.CenterScreen }; chatWith.Show(); } /// <summary> /// 客戶端 B /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void Button2_Click(object sender, EventArgs e) { ChatWith chatWith = new ChatWith(currentUserId: "UserB") { StartPosition = FormStartPosition.CenterScreen }; chatWith.Show(); } /// <summary> /// 客戶端 C /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void Button3_Click(object sender, EventArgs e) { ChatWith chatWith = new ChatWith(currentUserId: "UserC") { StartPosition = FormStartPosition.CenterScreen }; chatWith.Show(); } /// <summary> /// 客戶端 D /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void Button4_Click(object sender, EventArgs e) { ChatWith chatWith = new ChatWith(currentUserId: "UserD") { StartPosition = FormStartPosition.CenterScreen }; chatWith.Show(); } }View Code
2.4、客戶端表單
新建一個ChatWith表單：
代碼如下：
public partial class ChatWith : Form { public delegate void ChatWithDelegate(); public delegate void ChatWithDelegate<T1>(T1 obj1); public delegate void ChatWithDelegate<T1, T2>(T1 obj1, T2 obj2); public string CurrentUserId { get; } private IBus bus; public const string ConnStringMQ = "host=192.168.2.242:5672,192.168.2.165:5672;virtualHost=/;username=hello;password=world"; public const string FanoutExchange = "fanoutEC"; /// <summary> /// 有參建構式 /// </summary> /// <param name="currentUserId"></param> public ChatWith(string currentUserId) { InitializeComponent(); //在多執行緒程式中，新創建的執行緒不能訪問UI執行緒創建的視窗控制元件， //此時若想訪問表單的控制元件，可將表單建構式中的CheckForIllegalCrossThreadCalls設定為false， //這時執行緒就能安全地訪問表單控制元件了， CheckForIllegalCrossThreadCalls = false; CurrentUserId = currentUserId; } /// <summary> /// ShowMessage多載 /// </summary> /// <param name="msg"></param> private void ShowMessage(string msg) { if (InvokeRequired)//InvokeRequired：當前執行緒不是創建控制元件的執行緒時為true { BeginInvoke(new ChatWithDelegate<string>(ShowMessage), msg); } else { ListViewItem item = new ListViewItem(new string[] { DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss"), msg }); lvwReceiveMsg.Items.Insert(0, item); } } /// <summary> /// ShowMessage多載 /// </summary> /// <param name="toUserId"></param> /// <param name="msg"></param> private void ShowMessage(string toUserId, string msg) { if (InvokeRequired) { BeginInvoke(new ChatWithDelegate<string, string>(ShowMessage), toUserId, msg); } else { ListViewItem item = new ListViewItem(new string[] { DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss"), toUserId, msg }); lvwReceiveMsg.Items.Insert(0, item); } } /// <summary> /// 系結佇列并訂閱 /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void ChatWith_Load(object sender, EventArgs e) { cmbOnLine.SelectedIndex = 0; Text = Text + $"[{CurrentUserId}]"; //這里不能使用using，否則訂閱者立即就釋放了，訂閱不到訊息， bus = RabbitHutch.CreateBus(ConnStringMQ); { if (bus.IsConnected) { var exchange = bus.Advanced.ExchangeDeclare(name: FanoutExchange, type: ExchangeType.Fanout); var queue = bus.Advanced.QueueDeclare(name: $"{FanoutExchange}_queue_{CurrentUserId}"); bus.Advanced.Bind(exchange: exchange, queue: queue, routingKey: ""); bus.Advanced.Consume(queue, registration => { registration.Add<MessageBody>((message, info) => { if (message.Body.ToUserId == CurrentUserId) { ShowMessage(message.Body.FromUserId, message.Body.Message); } }); }); } else { ShowMessage("服務器連接失敗，"); } } } /// <summary> /// 發送 /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void btnSend_Click(object sender, EventArgs e) { try { using (var bus = RabbitHutch.CreateBus(ConnStringMQ)) { if (bus.IsConnected) { if (cmbOnLine.Text == "*")//群發 { foreach (var item in cmbOnLine.Items.Cast<string>().Where(s => s != "*" && s != CurrentUserId)) { var exchange = bus.Advanced.ExchangeDeclare(name: FanoutExchange, type: ExchangeType.Fanout); var messageBody = new MessageBody { FromUserId = CurrentUserId, Message = txtSendMsg.Text, ToUserId = item }; bus.Advanced.Publish(exchange: exchange, routingKey: "", mandatory: false, message: new Message<MessageBody>(messageBody)); } } else//私聊 { var exchange = bus.Advanced.ExchangeDeclare(name: FanoutExchange, type: ExchangeType.Fanout); var messageBody = new MessageBody { FromUserId = CurrentUserId, Message = txtSendMsg.Text, ToUserId = cmbOnLine.Text }; bus.Advanced.Publish(exchange: exchange, routingKey: "", mandatory: false, message: new Message<MessageBody>(messageBody)); } } else { ShowMessage("發送訊息失敗，"); } } } catch (Exception ex) { ShowMessage(ex.Message); } } /// <summary> /// 關閉 /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void btnClose_Click(object sender, EventArgs e) { Close(); } /// <summary> /// 表單關閉事件 /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void ChatWith_FormClosed(object sender, FormClosedEventArgs e) { bus?.Dispose(); } }View Code
2.5、運行結果
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標籤：C#
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