客戶端：

介面：

程式碼：

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

namespace Test2.Client
{
    
 
public partial class Form1 : Form
    {
        Socket clientSocket;
        IPEndPoint ipEndPoint;
        public Form1()
        {
            InitializeComponent();
            button1.Text = "連線";
            button2.Text = "傳送";
            button3.Text = "關閉";
        }
        private void button1_Click(object
 
 sender, EventArgs e)
        {
            clientSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
            ipEndPoint = new IPEndPoint(IPAddress.Parse("xxxxxxxxx"), 52555);
            clientSocket.Connect(ipEndPoint);
        }

        private void button2_Click(object
 
 sender, EventArgs e)
        {
            clientSocket.Send(System.Text.Encoding.UTF8.GetBytes(textBox1.Text));
            
        }

        private void button3_Click(object sender, EventArgs e)
        {
            SafeClose(clientSocket);
        }
        public  void SafeClose( Socket socket)
        {
            if (socket == null)
                return;

            if (!socket.Connected)
                return;

            try
            {
                socket.Shutdown(SocketShutdown.Both);
            }
            catch
            {
            }

            try
            {
                socket.Close();
            }
            catch
            {
            }
        }
    }
}

伺服器端：

介面：

程式碼：

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

namespace Test2.Server
{
    public partial class Form1 : Form
    {
  
        public Form1()
        {
            InitializeComponent();
            this.FormClosed += Form1_FormClosed;
        }

        private void Form1_FormClosed(object sender, FormClosedEventArgs e)
        {
            SafeClose(socketSend);
        }
        public void SafeClose( Socket socket)
        {
            if (socket == null)
                return;

            if (!socket.Connected)
                return;

            try
            {
                socket.Shutdown(SocketShutdown.Both);
            }
            catch
            {
            }

            try
            {
                socket.Close();
            }
            catch
            {
            }
        }


        Socket socketSend;
        private void button1_Click(object sender, EventArgs e)
        {
            try
            {
                //點選開始監聽時 在服務端建立一個負責監聽IP和埠號的Socket
                Socket socketWatch = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
                IPAddress ip = IPAddress.Any;                //建立物件埠
                IPEndPoint point = new IPEndPoint(ip, Convert.ToInt32(52555));
                socketWatch.Bind(point);//繫結埠號
                MessageBox.Show("Watching");
                socketWatch.Listen(10);//設定監聽
                                       //建立監聽執行緒
                Thread thread = new Thread(Listen);
                thread.IsBackground = true;
                thread.Start(socketWatch);
            }
            catch { }

        }

        void Listen(object o)
        {
            try
            {
                Socket socketWatch = o as Socket;
                while (true)
                {
                    socketSend = socketWatch.Accept();//等待接收客戶端連線
                    //ShowMsg(socketSend.RemoteEndPoint.ToString() + ":" + "連線成功!");
                    //開啟一個新執行緒，執行接收訊息方法
                    Thread r_thread = new Thread(Received);
                    r_thread.IsBackground = true;
                    r_thread.Start(socketSend);
                }
            }
            catch { }
        }

        void Received(object o)
        {
            try
            {
                Socket socketSend = o as Socket;
                while (true)
                {
                    //客戶端連線伺服器成功後，伺服器接收客戶端傳送的訊息
                    byte[] buffer = new byte[1024 * 1024 * 3];
                    //實際接收到的有效位元組數
                    int len = socketSend.Receive(buffer);
                    if (len == 0)
                    {
                        break;
                    }
                    string str = Encoding.UTF8.GetString(buffer, 0, len);

                    this.Invoke(new Action(() =>
                    {
                        listBox1.Items.Add(str + "\r\n");
                    }));
                }
            }
            catch { }
        }
    }
}