c#使用Socket实现局域网内通信

服务器端代码：

 using System;
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.Data;
 using System.Drawing;
 using System.Linq;
 using System.Net.Sockets;
 using System.Net;
 using System.Text;
 using System.Threading.Tasks;
 using System.Windows.Forms;
 using System.Threading;
 using System.IO;

 namespace socket通信
 {
     public partial class SERVER : Form
     {
         public SERVER()
         {
             InitializeComponent();
         }
         Socket socketSend;
         private void Form1_Load(object sender, EventArgs e)
         {
             this.ActiveControl = this.btnListen;
             txtaidip.Text = GetIpAdress();
             //txtport.Text = "80";
             Control.CheckForIllegalCrossThreadCalls = false;
         }
         //将远程连接的IP地址和Socket存放到集合中
         Dictionary<string, Socket> diSocket = new Dictionary<string, Socket>();
         private void button1_Click(object sender, EventArgs e)
         {
             try
             {
                 //创建一个socket，负责监听IP地址和端口号
                 Socket socketWatch = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
                 IPAddress ip = IPAddress.Parse(txtaidip.Text.Trim());        //提供一个IP地址
                 IPEndPoint point = new IPEndPoint(ip, );      //端口号，其中包括了IP地址

                 socketWatch.Bind(point);            //绑定IP地址和端口
                 ShowMsg("监听成功");
                 socketWatch.Listen();             //设置监听队列，最多允许同时10个连接，（0表示不限制）

                 Thread th = new Thread(Listen);
                 th.IsBackground = true;
                 th.Start(socketWatch);              //socketWatch是Listen()的参数
             }
             catch
             {

             }

         }

         private void ShowMsg(string str)
         {
             txtReceMsg.AppendText(str + "\r\n");
         }

         /// <summary>
         ///  //获取本机IP地址
         /// </summary>
         /// <returns></returns>
         private string GetIpAdress()
         {
             try
             {
                 string HostName = Dns.GetHostName(); //得到主机名
                 IPHostEntry IpEntry = Dns.GetHostEntry(HostName);
                 for (int i = ; i < IpEntry.AddressList.Length; i++)
                 {
                     //从IP地址列表中筛选出IPv4类型的IP地址
                     //AddressFamily.InterNetwork表示此IP为IPv4,
                     //AddressFamily.InterNetworkV6表示此地址为IPv6类型
                     if (IpEntry.AddressList[i].AddressFamily == AddressFamily.InterNetwork)
                     {
                         return IpEntry.AddressList[i].ToString();
                     }
                 }
                 return "";
             }
             catch (Exception ex)
             {
                 return ex.Message;
             }
         }

         /// <summary>
         /// 解决只能连接一个用户的问题
         /// </summary>
         private void Listen(Object o)
         {
             Socket socketWatch = o as Socket;
             while (true)
             {
                 try
                 {
                     //接下来等待客户端的连接
                     socketSend = socketWatch.Accept();   //为客户端创建一个负责通信的新的socket并接收来自客户端的请求
                     //将新的socket存放进集合中
                     diSocket.Add(socketSend.RemoteEndPoint.ToString(), socketSend);
                     //将远程连接的IP地址和端口号存入下拉框
                     cboUsers.Items.Add(socketSend.RemoteEndPoint.ToString());
                     ShowMsg(socketSend.RemoteEndPoint.ToString() + ":连接成功");     //192.168.0.103:连接成功
                     Thread th = new Thread(ReceiveSend);
                     //开启一个新线程不停接收来自客户端的消息
                     th.IsBackground = true;
                     th.Start(socketSend);
                 }
                 catch
                 {

                 }

             }
         }
         /// <summary>
         /// 服务器端不停的接收客户端发送过来的消息
         /// </summary>
         /// <param name="o"></param>
         private void ReceiveSend(Object o)
         {
             Socket socketSend = o as Socket;
             while (true)
             {
                 try
                 {
                     //客户端连接成功后，服务器应该接受客户端发出的消息
                     byte[] buffer = new byte[* * ];
                     int r = socketSend.Receive(buffer);         // 实际接收到的有效字节数
                     if (r == )
                     {
                         break;
                     }
                     string str = Encoding.UTF8.GetString(buffer, , r);         //将字节流转换为string【str就是客户端向服务器发送的字符串】
                     ShowMsg(socketSend.RemoteEndPoint.ToString() + ":" + str);         //远程客户端连接：接收客户端发送的内容

                 }
                 catch
                 {

                 }
             }
         }

         private void btnSendMsg_Click(object sender, EventArgs e)
         {           //将服务器端的信息发送给客户端
             string str = txtSendMsg.Text.Trim();
             byte[] buffer = System.Text.Encoding.UTF8.GetBytes(str);
             //socketSend.Send(buffer);
             //获得用户在下拉框中选中的IP地址，根据IP地址找到对应的socket,然后发送消息
             string ip = cboUsers.SelectedIndex.ToString();
             diSocket[ip].Send(buffer);
             txtReceMsg.AppendText(GetIpAdress() + ">>" + txtSendMsg.Text.Trim() + "\r\n");
             txtSendMsg.Text = "";       //清空文本框
         }

         //在文本框中输入信息后按【Enter】键，触发【发送消息】事件
         private void txtSendMsg_KeyPress(object sender, KeyPressEventArgs e)
         {
             if (e.KeyChar == '\r')
             {
                 btnSendMsg_Click(sender, e);
             }
         }
     }
 }

客户端代码：

 using System;
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.Data;
 using System.Drawing;
 using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
 using System.Windows.Forms;
 using System.Net.Sockets;
 using System.Net;
 using System.Threading;

 namespace socket通信客户端
 {
     public partial class CLIENT : Form
     {
         public CLIENT()
         {
             InitializeComponent();
         }

         Socket socketSend;
         /// <summary>
         ///  //获取本机IP地址
         /// </summary>
         /// <returns></returns>
         private string GetIpAdress()
         {
             try
             {
                 string HostName = Dns.GetHostName(); //得到主机名
                 IPHostEntry IpEntry = Dns.GetHostEntry(HostName);
                 for (int i = ; i < IpEntry.AddressList.Length; i++)
                 {
                     //从IP地址列表中筛选出IPv4类型的IP地址
                     //AddressFamily.InterNetwork表示此IP为IPv4,
                     //AddressFamily.InterNetworkV6表示此地址为IPv6类型
                     if (IpEntry.AddressList[i].AddressFamily == AddressFamily.InterNetwork)
                     {
                         return IpEntry.AddressList[i].ToString();
                     }
                 }
                 return "";
             }
             catch (Exception ex)
             {
                 return ex.Message;
             }
         }

         private void Form1_Load(object sender, EventArgs e)
         {
             //txtlocalip.Text = GetIpAdress();
             //txtport.Text = "8080";
             Control.CheckForIllegalCrossThreadCalls = false;
             this.ActiveControl = this.btnConnection;

         }

         private void btnConnection_Click(object sender, EventArgs e)
         {
             try
             {
                 //创建一个socket用来连接服务器
                 socketSend = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
                 IPAddress ip = IPAddress.Parse(txtaidip.Text.Trim());      //获取IP地址
                 IPEndPoint ipep = new IPEndPoint(ip, Convert.ToInt32(txtport.Text.Trim()));

                 //获得要连接的远程服务器的IP地址和端口号
                 socketSend.Connect(ipep);
                 showMSG("连接成功");
                 //创建一个线程，用来不断接收服务器端发送的信息
                 Thread th = new Thread(ReceiveMessage);
                 th.IsBackground = true;     //后台线程
                 th.Start(socketSend);       //socketSend是Start()的参数
             }
             catch
             {

             }

         }

         private void showMSG(string str)
         {
             txtReceMsg.AppendText(str + "\r\n");
         }

         private void btnSendMsg_Click(object sender, EventArgs e)
         {
             string str = txtSendMsg.Text.Trim();
             byte[] buffer = System.Text.Encoding.UTF8.GetBytes(str);
             socketSend.Send(buffer);
             txtReceMsg.AppendText(GetIpAdress() + ">>" + txtSendMsg.Text.Trim() + "\r\n");
             txtSendMsg.Text = "";
         }

         private void txtMsg_KeyPress(object sender, KeyPressEventArgs e)
         {
             if (e.KeyChar == '\r')
             {
                 this.btnSendMsg_Click(sender, e);
             }
         }
         /// <summary>
         /// 不停地接收服务器端发送来的信息
         /// </summary>
         /// <param name="o"></param>
         private void ReceiveMessage(Object o)
         {
             Socket socketSend = o as Socket;
             try
             {
                 while (true)
                 {
                     byte[] buffer = new byte[ *  * ];
                     int r = socketSend.Receive(buffer);
                     if (r == )
                     {
                         break;
                     }
                     string str = Encoding.UTF8.GetString(buffer, , r);
                     showMSG(socketSend.RemoteEndPoint.ToString() + ":" + str);

                 }
             }
             catch
             {

             }

         }
     }

 }