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();