SendTo(byte[] data,EndPoint Remote)

using System;
using System.Collections.Generic;
using System.Text;
using System.Net;
using System.Net.Sockets;

namespace UDP
{
 class Program
 {
  static void Main(string[] args)
  {
   int recv;
   byte[] data = new byte[1024];

   //得到本机IP，设置TCP端口号   
   IPEndPoint ip = new IPEndPoint(IPAddress.Any, 8001);
   Socket newsock = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);

   //绑定网络地址
   newsock.Bind(ip);

   Console.WriteLine("This is a Server, host name is {0}", Dns.GetHostName());

   //等待客户机连接
   Console.WriteLine("Waiting for a client");

   //得到客户机IP
   IPEndPoint sender = new IPEndPoint(IPAddress.Any, 0);
   EndPoint Remote = (EndPoint)(sender);
   recv = newsock.ReceiveFrom(data, ref Remote);
   Console.WriteLine("Message received from {0}: ", Remote.ToString());
   Console.WriteLine(Encoding.ASCII.GetString(data, 0, recv));

   //客户机连接成功后，发送信息
   string welcome = "你好 ! ";

   //字符串与字节数组相互转换
   data = Encoding.ASCII.GetBytes(welcome);

   //发送信息
   newsock.SendTo(data, data.Length, SocketFlags.None, Remote);
   while (true)
   {
    data = new byte[1024];
    //发送接收信息
    recv = newsock.ReceiveFrom(data, ref Remote);
    Console.WriteLine(Encoding.ASCII.GetString(data, 0, recv));
    newsock.SendTo(data, recv, SocketFlags.None, Remote);
   }
  }

 }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net;
using System.Net.Sockets;

namespace UDPClient
{
 class Program
 {
  static void Main(string[] args)
  {
   byte[] data = new byte[1024];
   string input, stringData;

   //构建TCP 服务器
   Console.WriteLine("This is a Client, host name is {0}", Dns.GetHostName());

   //设置服务IP，设置TCP端口号
   IPEndPoint ip = new IPEndPoint(IPAddress.Parse("127.0.0.1"), 8001);

   //定义网络类型，数据连接类型和网络协议UDP
   Socket server = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);

   string welcome = "你好! ";
   data = Encoding.ASCII.GetBytes(welcome);
   server.SendTo(data, data.Length, SocketFlags.None, ip);
   IPEndPoint sender = new IPEndPoint(IPAddress.Any, 0);
   EndPoint Remote = (EndPoint)sender;

   data = new byte[1024];
   //对于不存在的IP地址，加入此行代码后，可以在指定时间内解除阻塞模式限制
   int recv = server.ReceiveFrom(data, ref Remote);
   Console.WriteLine("Message received from {0}: ", Remote.ToString());
   Console.WriteLine(Encoding.ASCII.GetString(data, 0, recv));
   while (true)
   {
    input = Console.ReadLine();
    if (input == "exit")
     break;
    server.SendTo(Encoding.ASCII.GetBytes(input), Remote);
    data = new byte[1024];
    recv = server.ReceiveFrom(data, ref Remote);
    stringData = Encoding.ASCII.GetString(data, 0, recv);
    Console.WriteLine(stringData);
   }
   Console.WriteLine("Stopping Client.");
   server.Close();
  }

 }
}

using System;
using System.Net;
using System.Net.Sockets;
using System.Text;

public class Custom
{
 // 设置IP，IPV6
 private static readonly IPAddress GroupAddress = IPAddress.Parse("IP地址");
 // 设置端口
 private const int GroupPort = 11000;

 private static void StartListener()
 {
  bool done = false;

  UdpClient listener = new UdpClient();

  IPEndPoint groupEP = new IPEndPoint(GroupAddress, GroupPort);

  try
  {
   //IPV6，组播
   listener.JoinMulticastGroup(GroupAddress);

   listener.Connect(groupEP);

   while (!done)
   {
    Console.WriteLine("Waiting for broadcast");

    byte[] bytes = listener.Receive(ref groupEP);

    Console.WriteLine("Received broadcast from {0} :\n {1}\n", groupEP.ToString(), Encoding.ASCII.GetString(bytes, 0, bytes.Length));
   }

   listener.Close();

  }
  catch (Exception e)
  {
   Console.WriteLine(e.ToString());
  }

 }

 public static int Main(String[] args)
 {
  StartListener();

  return 0;
 }
}

using System;
using System.Net;
using System.Net.Sockets;
using System.Text;

public class Client
{

 private static IPAddress GroupAddress = IPAddress.Parse("IP地址");

 private static int GroupPort = 11000;

 private static void Send(String message)
 {
  UdpClient sender = new UdpClient();

  IPEndPoint groupEP = new IPEndPoint(GroupAddress, GroupPort);

  try
  {
   Console.WriteLine("Sending datagram : {0}", message);

   byte[] bytes = Encoding.ASCII.GetBytes(message);

   sender.Send(bytes, bytes.Length, groupEP);

   sender.Close();

  }
  catch (Exception e)
  {
   Console.WriteLine(e.ToString());
  }

 }

 public static int Main(String[] args)
 {
  Send(args[0]);

  return 0;
 }
}

// 创建一个子线程

   Thread thread = new Thread(
    delegate()
    {
     try
     {
      //在这里写你的代码
     }
     catch (Exception )
     {

     }
    }
   );

   thread.Start();