C# socket

http://c.biancheng.net/socket/  

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

//服务端
namespace Test_Socket_Server
{
    class Program
    {
        //声明套接字实例，用于与客户端通信
        static Socket listenSocket;
        //定义字典集合，用于存储客户端信息(键：客户端ip、端口，值：与客户端通信套接字)
        static Dictionary<string, Socket> clientConnectionItems = new Dictionary<string, Socket>();
        static void Main(string[] args)
        {
            //定义套接字用于监听
            listenSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
            //将ip、端口绑定到网络终结点
            IPEndPoint ip = new IPEndPoint(IPAddress.Parse("127.0.0.1"), 5678);
            //绑定终结点
            listenSocket.Bind(ip);
            //设定监听的队列长度最大数量为10
            listenSocket.Listen(10);

            Console.WriteLine("服务端开始监听！");

            #region 创建监听线程
            //开启监听线程
            Thread thread = new Thread(ListenClient);
            //设置为后台同步线程，随着主线程结束而结束
            thread.IsBackground = true;
            //开启此线程
            thread.Start();
            #endregion

            Console.ReadKey();
        }

        static void ListenClient()
        {
            while (true)
            {
                Socket newSocket = listenSocket.Accept();
                //客户端网络终结点号
                string clientRemoteEndPoint = newSocket.RemoteEndPoint.ToString();

                //通知已存储客户端，新客户端连接
                if (clientConnectionItems.Count > 0)
                {
                    foreach (var item in clientConnectionItems)
                    {
                        item.Value.Send(new UTF8Encoding().GetBytes("服务端：客户端" + newSocket.RemoteEndPoint.ToString() + "已上线！"));
                    }

                    clientConnectionItems.Add(clientRemoteEndPoint, newSocket);
                }
                else
                {
                    //存储客户端
                    clientConnectionItems.Add(clientRemoteEndPoint, newSocket);
                }

                Console.WriteLine("客户端" + clientRemoteEndPoint + "连接到服务端！");

                //获取客户端的IP和端口号  
                IPAddress clientIP = (newSocket.RemoteEndPoint as IPEndPoint).Address;
                int clientPort = (newSocket.RemoteEndPoint as IPEndPoint).Port;

                //向客户端发送连接成功的提示信息
                string message = "本地IP：" + clientIP + " 本地端口：" + clientPort.ToString() + " 连接服务端成功！";
                byte[] msg = Encoding.UTF8.GetBytes(message);
                newSocket.Send(msg);

                //创建一个通信线程      
                Thread thread = new Thread(ReceiveMessage);
                thread.IsBackground = true;
                thread.Start(newSocket);
            }
        }

        // 接收客户端发来的信息
        static void ReceiveMessage(Object socket)
        {
            Socket newSocket = (Socket)socket;
            //Socket newSocket = socket as Socket;

            //监听消息
            while (true)
            {
                //创建一个缓冲区
                byte[] buffer = new byte[1024];
                try
                {
                    //存入缓存并获取实际接收的字节数
                    int length = newSocket.Receive(buffer);
                    //将接受到的字节数组转换为字符串 
                    string message = Encoding.UTF8.GetString(buffer, 0, length);
                    //string message = new UTF8Encoding().GetString(buffer);

                    Console.WriteLine("客户端：" + newSocket.RemoteEndPoint.ToString() + message);

                    //发送客户端数据
                    if (clientConnectionItems.Count > 0)
                    {
                        foreach (var item in clientConnectionItems)
                        {
                            item.Value.Send(Encoding.UTF8.GetBytes(newSocket.RemoteEndPoint + "：" + message));
                        }
                    }
                }
                catch
                {
                    //提示套接字监听异常
                    Console.WriteLine("客户端：" + newSocket.RemoteEndPoint.ToString() + "断开！");
                    clientConnectionItems.Remove(newSocket.RemoteEndPoint.ToString());
                    //关闭
                    newSocket.Close();
                    break;
                }
            }
        }
    }
}

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

//客户端
namespace Test_CSharp_Client
{
    class Program
    {
        static Socket socket;
        static void Main(string[] args)
        {
            socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
            //创建要连接的ip
            IPEndPoint ip = new IPEndPoint(IPAddress.Parse("127.0.0.1"), 5678);

            try
            {
                Console.WriteLine("发起连接！");
                socket.Connect(ip);
            }
            catch (Exception)
            {
                Console.WriteLine("连接失败！");
                return;
            }

            Thread thread = new Thread(ReceiveServerMessage);
            thread.IsBackground = true;
            thread.Start();

            while (true)
            {
                string message = Console.ReadLine();
                ClientSendMessage(message);
            }
        }

        //接收服务端信息
        public static void ReceiveServerMessage()
        {
            while (true)
            {
                //定义缓冲区
                byte[] buffer = new byte[1024];
                try
                {
                    //将客户端套接字接收到的数据存入缓冲区，并获取长度
                    int length = socket.Receive(buffer);

                    //将套接字获取到的字符数组转换为字符串  
                    string message = Encoding.UTF8.GetString(buffer, 0, length);
                    Console.WriteLine("服务器：" + message);
                }
                catch
                {
                    Console.WriteLine("远程服务器已经中断连接，不再接收来自服务端的消息！");
                    break;
                }
            }
        }

        //发送信息到服务端
        public static void ClientSendMessage(string message)
        {
            try
            {
                //将字符串转换为字节数组
                byte[] byteMessage = Encoding.UTF8.GetBytes(message);
                //发送
                socket.Send(byteMessage);
            }
            catch
            {
                Console.WriteLine("服务器异常，无法发送！");
            }
        }
    }
}