服務端代碼：

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

namespace UdpsocketServer
{
    class Program
    {
        static void Main(string[] args)
        {
            int recv;
            
 
byte[] revData = new byte[1024];
            byte[] sendData = new byte[1024];
            IPEndPoint ip = new IPEndPoint(IPAddress.Any, 6666);
            Socket newsock = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
            newsock.Bind(ip);
            Console.WriteLine(
 
"我是服務端，主機名：{0}", Dns.GetHostName());
            Console.WriteLine("等待客戶端連接.....");
            IPEndPoint sender = new IPEndPoint(IPAddress.Any, 0);
            EndPoint Remote = (EndPoint)(sender);
            recv = newsock.ReceiveFrom(revData, ref Remote);
            Console.WriteLine("我是服務端，客戶端{0}連接成功
 
", Remote.ToString());
            Console.WriteLine(Encoding.Unicode.GetString(revData, 0, recv));
            string welcome = "你好，我是服務器";
            sendData = Encoding.Unicode.GetBytes(welcome);
            newsock.SendTo(sendData, sendData.Length, SocketFlags.None, Remote);
            while (true)
            {
                sendData = new byte[1024];
                recv = newsock.ReceiveFrom(sendData, ref Remote);
                string recvData = string.Format("客戶端{0}發送：{1}", Remote.ToString(), Encoding.Unicode.GetString(sendData, 0, recv));
                Console.WriteLine(recvData);
                // string recvData =string.Format("服務器接收到數據{0}", Encoding.ASCII.GetString(data, 0, recv));
                // byte.Parse(recvData);
                string recvDateSucceed = string.Format("服務器已收到.");
                sendData = Encoding.Unicode.GetBytes(recvDateSucceed);
                newsock.SendTo(sendData, sendData.Length, SocketFlags.None, Remote);
            }
        }
    }
}

客戶端代碼：

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

namespace UdpsocketDemo
{
    class Program
    {
        static void Main(string[] args)
        {
            byte[] data = new byte[1024];
            string input, stringData;
            //構建TCP 服務器
            Console.WriteLine("這是客戶端, 主機名是 {0}", Dns.GetHostName());
            //設置服務IP，設置TCP端口號
            IPEndPoint ip = new IPEndPoint(IPAddress.Parse("127.0.0.1"), 6666);
            //定義網絡類型，數據連接類型和網絡協議UDP
            Socket server = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
            string welcome = "你好服務器，我是客戶端! ";
            data = Encoding.Unicode.GetBytes(welcome);
            server.SendTo(data, data.Length, SocketFlags.None, ip);
            IPEndPoint sender = new IPEndPoint(IPAddress.Any, 0);
            EndPoint Remote = (EndPoint)sender;

            byte[] sendData = new byte[1024];
            //對於不存在的IP地址，加入此行代碼後，可以在指定時間內解除阻塞模式限制
            int recv = server.ReceiveFrom(sendData, ref Remote);
            Console.WriteLine("我是客戶端，從服務器端： {0}接收到消息 ", Remote.ToString());
            Console.WriteLine(Encoding.Unicode.GetString(sendData, 0, recv));
            while (true)
            {
                input = Console.ReadLine();
                //退出
                if (input == "exit")
                    break;
                server.SendTo(Encoding.Unicode.GetBytes(input), Remote);
                byte[] recvData = new byte[1024];
                recv = server.ReceiveFrom(recvData, ref Remote);
                stringData = string.Format("服務器{0}發送：{1}", Remote.ToString(), Encoding.Unicode.GetString(recvData, 0, recv));
                Console.WriteLine(stringData);
            }
            Console.WriteLine("服務停止.");
            server.Close();

        }

    }
}

udpsocket 通信C#例子