C#使用Socket实现局域网聊天

using System; 
using System.Collections.Generic; 
using System.Drawing; 
using System.Windows.Forms; 
using System.Net; 
using System.Net.Sockets; 
using System.Threading; 
using System.IO; 
using System.Text; 
using System.Text.RegularExpressions; 
 
namespace Server 
{ 
  public partial class MainForm : Form 
  { 
    private TcpListener listener; 
     
    private Dictionary<String,TcpClient> socketList; 
    private bool tag = true; 
    private StringBuilder charList; 
     
    public MainForm() 
    { 
      InitializeComponent(); 
      Control.CheckForIllegalCrossThreadCalls = false; 
    } 
     
    void Bu_StartClick(object sender, EventArgs e) 
    { 
      cb_chatList.Items.Clear(); 
      selectChat.Text=""; 
      int port = 8888; 
      //创建服务端，并且启动 
      try{ 
        listener = new TcpListener(IPAddress.Parse(ipAddress()),port); 
        listener.Start();   
         
        bu_Start.Enabled = false; 
        bu_stop.Enabled = true; 
      }catch(Exception ex) 
      { 
        MessageBox.Show("服务器启动失败， 原因："+ex.Message); 
        bu_Start.Enabled = true; 
        bu_stop.Enabled = false; 
        return; 
      } 
      selectChat.Text = "服务器启动成功，访问IP："+ipAddress()+" 端口号："+port; 
       
      //记录住连接的客户端 
      socketList = new Dictionary<String,TcpClient>(); 
      charList = new StringBuilder(); 
       
      //使用多线程，用于多个客户端接入 
      Thread th = new Thread(new ThreadStart(executeTask)); 
      th.Start(); 
    } 
    public void executeTask() 
    { 
      while(tag) 
      { 
        //等待用户连接 
        TcpClient client = null; 
        try{ 
          client = listener.AcceptTcpClient(); 
        }catch(Exception) 
        { 
        } 
        Thread th = new Thread(executeRead); 
        th.Start((Object)client); 
      } 
    } 
    public void executeRead(Object pamars) 
    { 
      //永久监听读取客户端 
      TcpClient client = pamars as TcpClient; 
      while(tag) 
      { 
        NetworkStream ns = client.GetStream(); 
        StreamReader sr = new StreamReader(ns); 
        String msg = String.Empty; 
        String people = String.Empty; 
        try { 
          msg = sr.ReadLine(); 
          if(msg.IndexOf("<clientName>")!=-1) 
          { 
            msg = Regex.Split(msg,"=")[1]; 
            cb_chatList.Items.Add(msg);        
            charList.Append(msg).Append("<@>"); 
            socketList.Add(msg,client); 
            msg = "<br>欢迎【"+msg+"】光临<br>"; 
          } 
          selectChat.AppendText(msg.Replace("<br>","\r\n")); 
          sendMsg(String.Empty,msg); 
        } catch (Exception) { 
          //MessageBox.Show(ex.Message.ToString()); 
          break; 
        } 
      } 
    } 
    public void sendMsg(String target,String msg) 
    { 
      if(String.Empty!=target) 
      { 
        TcpClient client = socketList[target]; 
        StreamWriter sw = new StreamWriter(client.GetStream()); 
        sw.WriteLine(msg); 
        sw.Flush();  
      }else{ 
        Dictionary<String,TcpClient>.KeyCollection keyColl = socketList.Keys; 
        foreach (String name in keyColl)  
        { 
          StreamWriter sw = new StreamWriter(socketList[name].GetStream()); 
          sw.WriteLine(msg+"<@=@>"+charList.ToString()); 
          sw.Flush();        
        } 
      } 
    } 
    /*根据计算名获取IP地址*/ 
    public String ipAddress() 
    { 
      IPAddress[] address = Dns.GetHostAddresses(Dns.GetHostName()); 
      return address[2].ToString(); 
    } 
     
    void ServerFromFormClosing(object sender, FormClosingEventArgs e) 
    { 
      e.Cancel = false; 
      if(tag) 
        tag = false; 
      if(listener!=null) 
        listener.Stop(); 
    } 
     
    void Bu_stopClick(object sender, EventArgs e) 
    { 
      bu_Start.Enabled = true; 
      bu_stop.Enabled = false; 
      if(tag) 
        tag = false; 
      if(listener!=null) 
        listener.Stop(); 
    } 
  } 
} 

using System; 
using System.Drawing; 
using System.Windows.Forms; 
using System.Threading; 
using System.Net; 
using System.Net.Sockets; 
using System.IO; 
using System.Text; 
using System.Text.RegularExpressions; 
 
namespace Client 
{ 
  public partial class MainForm : Form 
  { 
    private System.Windows.Forms.Timer closeWindowTimer; 
     
    private StreamReader sr; 
    private StreamWriter sw; 
    private TcpClient tc; 
    private ClientLong cl; 
    private bool tag = true; 
       
    public MainForm(TcpClient tcp,ClientLong clo) 
    { 
      cl = clo; 
      tc = tcp; 
      InitializeComponent(); 
      Control.CheckForIllegalCrossThreadCalls = false; 
      bu_simple.Hide(); 
    } 
    void ClientFromLoad(object sender, EventArgs e) 
    { 
      PiayCheckedChanged(); 
    } 
     
    /*事件方法*/ 
    public void PiayCheckedChanged() 
    { 
      closeWindowTimer = new System.Windows.Forms.Timer(); 
      closeWindowTimer.Interval = 1000; 
      closeWindowTimer.Tick += new EventHandler(theout); 
      closeWindowTimer.Start(); 
    } 
     
    /*执行的事件*/ 
    public void theout(object source, EventArgs e) 
    { 
      //这里单独开一个线程用来显示信息 
      try{ 
        Thread t1 = new Thread(new ThreadStart(readMsg)); 
        t1.Start(); 
      }catch(Exception) 
      { 
      } 
    } 
    void readMsg() 
    { 
      if(tag && tc!=null){ 
        sr = new StreamReader(tc.GetStream()); 
        String msg = sr.ReadLine(); 
        String[] address = Regex.Split(msg,"<@=@>"); 
        chatText.AppendText(address[0].Replace("<br>","\r\n")); 
        address = Regex.Split(address[1],"<@>"); 
        cb_chatList.Items.Clear(); 
        foreach (String s in address) 
        { 
          if(!String.IsNullOrEmpty(s) && s != cl.clientName) 
            cb_chatList.Items.Add(s);         
        } 
      } 
    } 
    void Button1Click(object sender, EventArgs e) 
    { 
      if(String.IsNullOrEmpty(textBox2.Text)){ 
        MessageBox.Show("请输入消息");return; 
      } 
      sw = new StreamWriter(tc.GetStream()); 
      sw.WriteLine("<br>"+cl.clientName+"　　"+DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss")+"<br>　"+textBox2.Text); 
      textBox2.Text = ""; 
      sw.Flush(); 
    } 
    void Bu_exitClick(object sender, EventArgs e) 
    { 
      MainFormFormClosing(null,null); 
    } 
    void Button2Click(object sender, EventArgs e) 
    { 
      chatText.Text = "";  
    } 
    void MainFormFormClosing(object sender, FormClosingEventArgs e) 
    { 
      closeWindowTimer.Stop(); 
      cl.Close(); 
      tag = false; 
      if(sr!=null) 
        sr.Close(); 
      if(sw!=null) 
        sw.Close(); 
    } 
    void Bu_simpleClick(object sender, EventArgs e) 
    { 
      String selected = cb_chatList.Text; 
      if(selected==null) 
      { 
        MessageBox.Show("请选择单聊对象"); 
        return; 
      } 
    } 
  } 
}