详解C# 网络编程系列：实现类似QQ的即时通信程序

 // 启动服务器 // 根据博客中协议的设计部分 // 客户端先向服务器发送登录请求，然后通过服务器返回的端口号 // 再与服务器建立连接 // 所以启动服务按钮事件中有两个套接字：一个是接收客户端信息套接字和 // 监听客户端连接套接字 private void btnStart_Click(object sender, EventArgs e) { // 创建接收套接字 serverIp = IPAddress.Parse(txbServerIP.Text); serverIPEndPoint = new IPEndPoint(serverIp, int.Parse(txbServerport.Text)); receiveUdpClient = new UdpClient(serverIPEndPoint); // 启动接收线程 Thread receiveThread = new Thread(ReceiveMessage); receiveThread.Start(); btnStart.Enabled = false; btnStop.Enabled = true; // 随机指定监听端口 Random random = new Random(); tcpPort = random.Next(port + 1, 65536); // 创建监听套接字 tcpListener = new TcpListener(serverIp, tcpPort); tcpListener.Start(); // 启动监听线程 Thread listenThread = new Thread(ListenClientConnect); listenThread.Start(); AddItemToListBox(string.Format("服务器线程{0}启动，监听端口{1}",serverIPEndPoint,tcpPort)); } // 接收客户端发来的信息 private void ReceiveMessage() { IPEndPoint remoteIPEndPoint = new IPEndPoint(IPAddress.Any, 0); while (true) { try { // 关闭receiveUdpClient时下面一行代码会产生异常 byte[] receiveBytes = receiveUdpClient.Receive(ref remoteIPEndPoint); string message = Encoding.Unicode.GetString(receiveBytes, 0, receiveBytes.Length); // 显示消息内容 AddItemToListBox(string.Format("{0}:{1}",remoteIPEndPoint,message)); // 处理消息数据 // 根据协议的设计部分，从客户端发送来的消息是具有一定格式的 // 服务器接收消息后要对消息做处理 string[] splitstring = message.Split(','); // 解析用户端地址 string[] splitsubstring = splitstring[2].Split(':'); IPEndPoint clientIPEndPoint = new IPEndPoint(IPAddress.Parse(splitsubstring[0]), int.Parse(splitsubstring[1])); switch (splitstring[0]) { // 如果是登录信息，向客户端发送应答消息和广播有新用户登录消息 case "login": User user = new User(splitstring[1], clientIPEndPoint); // 往在线的用户列表添加新成员 userList.Add(user); AddItemToListBox(string.Format("用户{0}({1})加入", user.GetName(), user.GetIPEndPoint())); string sendString = "Accept," + tcpPort.ToString(); // 向客户端发送应答消息 SendtoClient(user, sendString); AddItemToListBox(string.Format("向{0}({1})发出：[{2}]", user.GetName(), user.GetIPEndPoint(), sendString)); for (int i = 0; i 

 // 登录服务器 private void btnlogin_Click(object sender, EventArgs e) { // 创建接受套接字 IPAddress clientIP = IPAddress.Parse(txtLocalIP.Text); clientIPEndPoint = new IPEndPoint(clientIP, int.Parse(txtlocalport.Text)); receiveUdpClient = new UdpClient(clientIPEndPoint); // 启动接收线程 Thread receiveThread = new Thread(ReceiveMessage); receiveThread.Start(); // 匿名发送 sendUdpClient = new UdpClient(0); // 启动发送线程 Thread sendThread = new Thread(SendMessage); sendThread.Start(string.Format("login,{0},{1}", txtusername.Text, clientIPEndPoint)); btnlogin.Enabled = false; btnLogout.Enabled = true; this.Text = txtusername.Text; } // 客户端接受服务器回应消息 private void ReceiveMessage() { IPEndPoint remoteIPEndPoint = new IPEndPoint(IPAddress.Any,0); while (true) { try { // 关闭receiveUdpClient时会产生异常 byte[] receiveBytes = receiveUdpClient.Receive(ref remoteIPEndPoint); string message = Encoding.Unicode.GetString(receiveBytes,0,receiveBytes.Length); // 处理消息 string[] splitstring = message.Split(','); switch (splitstring[0]) { case "Accept": try { tcpClient = new TcpClient(); tcpClient.Connect(remoteIPEndPoint.Address, int.Parse(splitstring[1])); if (tcpClient != null) { // 表示连接成功 networkStream = tcpClient.GetStream(); binaryReader = new BinaryReader(networkStream); } } catch { MessageBox.Show("连接失败", "异常"); } Thread getUserListThread = new Thread(GetUserList); getUserListThread.Start(); break; case "login": string userItem = splitstring[1] + "," + splitstring[2]; AddItemToListView(userItem); break; case "logout": RemoveItemFromListView(splitstring[1]); break; case "talk": for (int i = 0; i