【总结】学习Socket编写的聊天室小程序

        public Form1()
        {
            InitializeComponent();
            TextBox.CheckForIllegalCrossThreadCalls = false;
        } 

        //服务端 监听套接字
        Socket socketWatch = null;
        //服务端 监听线程
        Thread threadWatch = null;
        //字典集合：保存 通信套接字
        Dictionary<string, Socket> dictCon = new Dictionary<string, Socket>(); 

        private void btnStartListen_Click(object sender, EventArgs e)
        {

            try
            {
                //1.创建监听套接字 使用 ip4协议，流式传输，TCP连接
                socketWatch = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
                //2.绑定端口
                //2.1获取网络节点对象
                IPAddress address = IPAddress.Parse(txtIP.Text);
                IPEndPoint endPoint = new IPEndPoint(address, int.Parse(txtPort.Text));
                //2.2绑定端口（其实内部 就向系统的 端口表中 注册 了一个端口，并指定了当前程序句柄）
                socketWatch.Bind(endPoint);
                //2.3设置监听队列
                socketWatch.Listen(10);
                //2.4开始监听,调用监听线程 执行 监听套接字的 监听方法
                threadWatch = new Thread(WatchConnecting);
                threadWatch.IsBackground = true;
                threadWatch.Start();
                ShowMsg("枫伶忆,服务器启动啦！");
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
                throw;
            }


        } 

        void WatchConnecting()
        {
            //2.4开始监听：此方法会阻断当前线程，直到有 其它程序 连接过来，才执行完毕
            Socket sokMsg = socketWatch.Accept();
            //将当前连接成功的 【与客户端通信的套接字】 的 标识 保存起来，并显示到 列表中
            //将 远程客户端的 ip和端口 字符串 存入 列表
            this.lbOnline.Items.Add(sokMsg.RemoteEndPoint.ToString());
            //将 服务端的通信套接字 存入 字典集合
            dictCon.Add(sokMsg.RemoteEndPoint.ToString(), sokMsg);

            ShowMsg("有客户端连接了！");
            //2.5创建 通信线程
            Thread thrMsg = new Thread(ReceiveMsg);
            thrMsg.IsBackground = true;
            thrMsg.Start(sokMsg);
        }

        void ReceiveMsg(object obj)
        {
            try
            {
                Socket sokMsg = obj as Socket;
                //3.通信套接字 监听 客户端的 消息
                //3.1创建 消息缓存区
                byte[] arrMsg = new byte[1024 * 1024 * 1];
                while (isReceive)
                {
                    //3.2接收客户端的消息 并存入 缓存区,注意：Receive方法也会阻断当前的线程
                    sokMsg.Receive(arrMsg);
                    //3.3将接收到的消息 转成 字符串
                    string strMsg = System.Text.Encoding.UTF8.GetString(arrMsg);
                    //3.4将消息 显示到 文本框
                    ShowMsg(strMsg);
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
                throw;
            }
        }

        void ShowMsg(string strmsg)
        {
            this.txtShow.AppendText(strmsg + "\r\n");
        } 

        private void btnSend_Click_1(object sender, EventArgs e)
        {

            string strClient = this.lbOnline.Text;
            if (string.IsNullOrEmpty(strClient))
            {
                MessageBox.Show("请选择你要发送消息的客户端");
                return;
            }
            if (dictCon.ContainsKey(strClient))
            {
                string strMsg = this.txtInput.Text.Trim();
                ShowMsg("\r\n向客户端【" + strClient + "】说：" + strMsg);

                //使用 指定的 通信套接字 将 字符串 发送到 指定的客户端
                byte[] arrMsg = System.Text.Encoding.UTF8.GetBytes(strMsg);
                dictCon[strClient].Send(arrMsg);
            }
            this.txtInput.Text = "";
        }

        public Form1()
        {
            InitializeComponent();
            TextBox.CheckForIllegalCrossThreadCalls = false;
        } 

       //客户端 通信套接字
        Socket socketMsg = null;
        //客户端 通信线程
        Thread threadMsg = null;

        bool isRec = true;//标记任务

        private void btnConnect_Click(object sender, EventArgs e)
        {
            try
            {
                //1.创建监听套接字 使用 ip4协议，流式传输，TCP连接
                socketMsg = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
                //2.获取要连接的服务端 节点
                //2.1获取网络节点对象
                IPAddress address = IPAddress.Parse(txtIP.Text);
                IPEndPoint endPoint = new IPEndPoint(address, int.Parse(txtPort.Text));
                //3.向服务端 发送链接请求
                socketMsg.Connect(endPoint);
                ShowMsg("连接服务器成功~~！");
                //4.开启通信线程
                threadMsg = new Thread(RecevieMsg);
                threadMsg.IsBackground = true;
                threadMsg.Start();
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
                throw;
            }

        } 

        void RecevieMsg()
        {
            try
            {
                //3.1创建 消息缓存区
                byte[] arrMsg = new byte[1024 * 1024 * 1];
                while (isRec)
                {
                    socketMsg.Receive(arrMsg);
                    string strMsg = System.Text.Encoding.UTF8.GetString(arrMsg);
                    ShowMsg("\r\n服务器说：" + strMsg);
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
                throw;
            }
        } 

        private void btnSend_Click_1(object sender, EventArgs e)
        {
            string strMsg = this.txtInput.Text.Trim();
            byte[] arrMsg = System.Text.Encoding.UTF8.GetBytes(strMsg);
            socketMsg.Send(arrMsg);
            this.txtInput.Text = "";
        }

        void ShowMsg(string strmsg)
        {
            this.txtShow.AppendText(strmsg + "\r\n");
        }