即时通信

using System;
using System.Text;
using System.Net;
using System.Net.Sockets;
using System.Threading;
using System.Windows.Forms;

namespace ChatClient
{
 class Chat
 {
  public static UdpClient udpClient;
  public static IPEndPoint serverIP;
  public static ChatForm chatForm;
  public static Thread threadReceiveMsg;
       
  public static void start()
  {
   udpClient = new UdpClient(9876);
   serverIP = new IPEndPoint(IPAddress.Parse("172.16.3.51"), 9875);

   chatForm = new ChatForm();
   //chatForm.Show();

   byte[] byteMsg = null;
   byteMsg = Encoding.Default.GetBytes("I");
   udpClient.Send(byteMsg, byteMsg.Length, serverIP);

   threadReceiveMsg = new Thread(new ThreadStart(receiveMsg));
   threadReceiveMsg.IsBackground = true;
   threadReceiveMsg.Start();
  }

  public static void stop()
  {
   byte[] byteMsg = null;
   byteMsg = Encoding.Default.GetBytes("O");
   //udpClient.Send(byteMsg, byteMsg.Length, serverIP);

   threadReceiveMsg.Abort();
  }

  public static void receiveMsg()
  {
   while (true)
   {
    try
    {
     IPEndPoint remoteIP = new IPEndPoint(IPAddress.Any, 0);
     byte[] recBytes = udpClient.Receive(ref remoteIP);
     if (recBytes == null)
     {
      Thread.Sleep(1000);
      continue;
     }
     chatForm.Show();
     chatForm.showMsg(System.Text.Encoding.Default.GetString(recBytes),remoteIP.Address.ToString());
    }
    catch//(InvalidOperationException)
    {
     Thread.Sleep(3000);
    }
   }
  }

  public static void SendMsg(string msg, string remoteIP)
  {
   byte[] byteMsg = Encoding.Default.GetBytes(msg);
   udpClient.Send(byteMsg, byteMsg.Length, new IPEndPoint(IPAddress.Parse(remoteIP), 9876));
  }
 }
}