一.控制台程序使用 UDP 通信

创建控制台程序

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客户端

using System;
using System.Text;
using System.Net;
using System.Net.Sockets;
namespace Client
{
    class Program
    {
        static void Main(string[] args)
        {
            byte[] data = new byte[1024];

            //输出客户端信息
            Console.WriteLine("This is a Client, host name is {0}", Dns.GetHostName());

            //设置服务IP（这个IP地址是服务器的IP），设置端口号
            IPEndPoint ip = new IPEndPoint(IPAddress.Parse("192.168.0.178"), 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);

            //发送问候信息嘿服务器
            string welcome = "你好,服务器!";
            data = Encoding.UTF8.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.UTF8.GetString(data, 0, recv));
            int i = 0;
            while (true)
            {
                string s = "hello cqjtu!重交物联2019级" + i;
                Console.WriteLine(s);
                //发送数据
                server.SendTo(Encoding.UTF8.GetBytes(s), Remote);
                if (i == 50)
                {
                    break;
                }
                i++;
            }
            Console.WriteLine("Stopping Client.");
            server.Close();

        }
    }
}

服务器端

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

namespace Server
{
    class Program
    {
        static void Main(string[] args)
        {
            //数据大小
            int recv;
            //存储数据
            byte[] data = new byte[1024];

            //得到本机IP，设置UDP端口号         
            IPEndPoint ip = new IPEndPoint(IPAddress.Any, 8001);

            //新建套接字,基于IPv和4UDP协议
            //当 SocketType 为 Dgram 时，ProtocolType 始终为 Udp。当 SocketType 为 Stream 时，ProtocolType 始终为 Tcp
            Socket newsock = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);

            //绑定本机ip地址
            newsock.Bind(ip);

            //打印服务器ip地址
            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");

            //一直保持运行
            while (true)
            {
                //一直等待客户端连接
                try
                {
                    while (true)
                    {
                        //得到客户机IP
                        IPEndPoint sender = new IPEndPoint(IPAddress.Any, 0);
                        EndPoint Remote = (EndPoint)(sender);

                        //接受客户端消息
                        recv = newsock.ReceiveFrom(data, ref Remote);
                        Console.WriteLine("Message received from {0}: ", Remote.ToString());
                        Console.WriteLine(Encoding.UTF8.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.UTF8.GetBytes(welcome);

                        //发送信息
                        newsock.SendTo(data, data.Length, SocketFlags.None, Remote);

                        //一直接收客户端信息
                        while (true)
                        {

                            //1000ms无信息直接断开连接
                            if (!newsock.Poll(1000, SelectMode.SelectRead))
                            {
                                Console.WriteLine("连接中断!");
                                break;
                            }

                            data = new byte[1024];
                            //接收信息
                            recv = newsock.ReceiveFrom(data, ref Remote);
                            Console.WriteLine(Encoding.UTF8.GetString(data, 0, recv));

                        }
                    }

                }
                catch (System.Exception ex)
                {
                    Console.WriteLine(ex.Message);
                }
            }
            
           

        }
    }
}

效果

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二.Form窗口程序使用 TCP 通信

创建新的窗体应用后，客户端代码：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WindowsFormsApp1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            
        }

        private void button1_Click(object sender, EventArgs e)
        {
            try
            {
                /*
                 * 显示当前时间
                 */
                string str = "The current time: ";
                str += DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss");
                textBox1.AppendText(str + Environment.NewLine);
                /*
                 * 做好连接准备
                 */
                int port = 2000;
                string host = "192.168.0.178";//我室友的IP地址
                IPAddress ip = IPAddress.Parse(host);
                IPEndPoint ipe = new IPEndPoint(ip, port);//把ip和端口转化为IPEndPoint实例
                Socket c = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);//创建一个Socket
                /*
                 * 开始连接
                 */
                str = "Connect to server...";
                textBox1.AppendText(str + Environment.NewLine);
                c.Connect(ipe);//连接到服务器
                /*
                 *发送消息 
                 */
                string sendStr = textBox2.Text;
                str = "The message content: " + sendStr;
                textBox1.AppendText(str + Environment.NewLine);
                byte[] bs = Encoding.UTF8.GetBytes(sendStr);
                str = "Send the message to the server...";
                textBox1.AppendText(str + Environment.NewLine);
                c.Send(bs, bs.Length, 0);//发送信息
                /*
                 * 接收服务器端的反馈信息
                 */
                string recvStr = "";
                byte[] recvBytes = new byte[1024];
                int bytes;
                bytes = c.Receive(recvBytes, recvBytes.Length, 0);//从服务器端接受返回信息
                recvStr += Encoding.UTF8.GetString(recvBytes, 0, bytes);
                str = "The server feedback: " + recvStr;//显示服务器返回信息
                textBox1.AppendText(str + Environment.NewLine);
                /*
                 * 关闭socket
                 */
                c.Close();
            }
            catch (ArgumentNullException f)
            {
                string str = "ArgumentNullException: " + f.ToString();
                textBox1.AppendText(str + Environment.NewLine);
            }
            catch (SocketException f)
            {
                string str = "ArgumentNullException: " + f.ToString();
                textBox1.AppendText(str + Environment.NewLine);
            }
            textBox1.AppendText("" + Environment.NewLine);
            textBox2.Text = "";
        }
    }
}

服务器端：

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

namespace ConsoleApp3
{
    class Program
    {
        static void Main(string[] args)
        {
            /*
             * 做好连接准备
             */
            int i = 0;
            int port = 2000;
            string host = "192.168.0.178";
            IPAddress ip = IPAddress.Parse(host);
            IPEndPoint ipe = new IPEndPoint(ip, port);
            Socket s = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);//创建一个Socket类
            s.Bind(ipe);//绑定2000端口
            /*
             * 循环监听并处理消息
             */
            while (true)
            {
                i++;
                try
                {
                    Console.WriteLine("\t-----------------------------------------------");
                    Console.Write("Perform operations {0} :", i);
                    s.Listen(0);//开始监听
                    Console.WriteLine("1. Wait for connect...");
                    /*
                     * 实例一个新的socket端口
                     */
                    Socket temp = s.Accept();//为新建连接创建新的Socket。
                    Console.WriteLine("2. Get a connect");
                    /*
                     * 接收客户端发的消息并做解码处理
                     */
                    string recvStr = "";
                    byte[] recvBytes = new byte[1024];
                    int bytes;
                    bytes = temp.Receive(recvBytes, recvBytes.Length, 0);//从客户端接受信息
                    recvStr += Encoding.UTF8.GetString(recvBytes, 0, bytes);
                    Console.WriteLine("3. Server Get Message:{0}", recvStr);//把客户端传来的信息显示出来
                    /*
                     * 返回给客户端连接成功的消息
                     */
                    string sendStr = "Ok!Client send message sucessful!";
                    byte[] bs = Encoding.UTF8.GetBytes(sendStr);
                    temp.Send(bs, bs.Length, 0);//返回客户端成功信息
                    /*
                     * 关闭端口
                     */
                    temp.Close();
                    Console.WriteLine("4. Completed...");
                    Console.WriteLine("-----------------------------------------------------------------------");
                    Console.WriteLine("");
                    //s.Close();//关闭socket（由于再死循环中，所以不用写，但如果是单个接收，实例socket并完成任务后需关闭）
                }
                catch (ArgumentNullException e)
                {
                    Console.WriteLine("ArgumentNullException: {0}", e);
                }
                catch (SocketException e)
                {
                    Console.WriteLine("SocketException: {0}", e);
                }
            }
        }
    }
}