using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Windows.Forms;
//添加引用
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;
namespace SocketServer
{
    public partial class Form1 : Form
    {
        Thread mythread;//创建线程
        Socket socket;
        int port = 8000;//定义侦听端口号
        
        public Form1()//服务器端
        {
            InitializeComponent();

        }
        //获取本机IP地址
        public static IPAddress GetServerIP()
        {
            IPHostEntry ieh = Dns.GetHostEntry(Dns.GetHostName());
            return ieh.AddressList[0];
        }
        //监听
        private void BeginListen()
        {            
            socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
                        
            IPAddress ServerIp = GetServerIP();
            IPEndPoint iep = new IPEndPoint(ServerIp, port);
            socket.Bind(iep);

            toolStripStatusLabel1.Text = iep.ToString() + "正在监听...";
            byte[] byteMessage = new byte[100]; 
            while (true)
            {
                try
                {
                    socket.Listen(5);
                    Socket newSocket = socket.Accept();
                    newSocket.Receive(byteMessage);

                    string sTime = DateTime.Now.ToShortTimeString();
                    string msg = sTime + "-" + "信息来自：";
                    msg += newSocket.RemoteEndPoint.ToString() +" "+ Encoding.Default.GetString(byteMessage).Trim(new char[] {'\0'});
                    [color=#FF0000]this.richTextBox1.AppendText(msg + "\r\n");[/color]
                }
                catch (SocketException ex)
                {
                    toolStripStatusLabel1.Text += ex.ToString();
                }
            }            
        }
        private void btn_Listen_Click(object sender, EventArgs e)
        {
            try
            {
                mythread = new Thread(new ThreadStart(BeginListen));
                mythread.Start();
            }
            catch (System.Exception er)
            {
                MessageBox.Show(er.Message, "完成", MessageBoxButtons.OK, MessageBoxIcon.Stop);
            }
        }
        
    }
}

using System;
using System.Windows.Forms;
//添加引用
using System.Net;
using System.Net.Sockets;
using System.Text;
namespace SocketClient
{
    public partial class Form1 : Form
    {
        public Form1()//客户端
        {
            InitializeComponent();
        }       
        private void Form1_Load(object sender, EventArgs e)
        {
            //得到本机地址
            IPHostEntry ieh = Dns.GetHostEntry(Dns.GetHostName());
            txtIP.Text = ieh.AddressList[0].ToString();
        }
        private void btn_Send_Click(object sender, EventArgs e)
        {
            BeginSend();
        }
        //发送信息
        private void BeginSend()
        {
            string ip = txtIP.Text;
            string port = txtPort.Text;
            string msg = txtMsg.Text.Trim();
            
            Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);

            IPAddress serverIp = IPAddress.Parse(ip);
            int serverPort = Convert.ToInt32(port);
            IPEndPoint iep = new IPEndPoint(serverIp, serverPort);                        
            socket.Connect(iep);

            byte[] byteMessage;
            byteMessage = Encoding.ASCII.GetBytes(msg);
            socket.Send(byteMessage);
            socket.Shutdown(SocketShutdown.Both);
            socket.Close();            
        }        
    }
}