（三）一个工作任务引起的乱战——udp通信

先上代码。该代码是在问度娘的过程中搜到的，自己实验运行了下，可以使用（vs2010  net fram4.0）。服务端代码：

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!见到你很高兴！ ";

            //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];
                //发送接受信息             
                recv = newsock.ReceiveFrom(data, ref Remote);
                Console.WriteLine(Encoding.ASCII.GetString(data, 0, recv));
                newsock.SendTo(data, recv, SocketFlags.None, Remote);
            }
        }
    }
}

客户端代码：

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();
        }
    }
}

运行后，服务端与客户端能正确通信。
这些代码虽然在实际工作处理中不是特别完整，但是可以提供一个思路。