服务端的同步方式和异步方式

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

namespace EchoServer0328
{
    public class ClientState
    {
        public Socket socket;
        public byte[] readBuffer = new byte[1024];
    }
    internal class EchoServer
    {
        public const int port = 8888;
        static Socket serverSocket;
        static Dictionary clientDictionary = new Dictionary();
        static void Main()
        {
            serverSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
            serverSocket.Bind(new IPEndPoint(IPAddress.Any, port));
            serverSocket.Listen(10);
            Console.WriteLine("服务器启动成功");

            serverSocket.BeginAccept(AcceptCallBack, serverSocket);

            Console.Read();
        }

        private static void AcceptCallBack(IAsyncResult ar)
        {
            Socket listenSocket = ar.AsyncState as Socket;
            Socket clientSocket = listenSocket.EndAccept(ar);
            Console.WriteLine("新的客户端接入"+ clientSocket.RemoteEndPoint);
            ClientState state = new ClientState();
            state.socket = clientSocket;
            clientDictionary.Add(clientSocket, state);
            //开始接收
            clientSocket.BeginReceive(state.readBuffer, 0, state.readBuffer.Length, 0, ReceiveCallBack, state);
            //再次开始接受连接，循环接受
            serverSocket.BeginAccept(AcceptCallBack, serverSocket);
            
        }
        /// 

        /// 接收回调
        /// 
        /// 
        private static void ReceiveCallBack(IAsyncResult ar)
        {
            try
            {
                ClientState state = ar.AsyncState as ClientState;
                Socket clientSocket = state.socket;
                int length = clientSocket.EndReceive(ar);
                if (length == 0)
                {
                    clientSocket.Close();
                    clientDictionary.Remove(clientSocket);
                    Console.WriteLine("客户端关闭连接"+ clientSocket.RemoteEndPoint);
                    return;
                }
                string receiveString = Encoding.Default.GetString(state.readBuffer, 0, length);
                receiveString = clientSocket.RemoteEndPoint +":"+ receiveString;
                receiveString.Trim();
                byte[] sendBuffer = Encoding.Default.GetBytes(receiveString);
                //单发
                //clientSocket.Send(sendBuffer);
                //群发
                foreach (var item in clientDictionary.Values)
                {
                    item.socket.Send(sendBuffer);
                }
                //再次开始接收数据，循环接收
                clientSocket.BeginReceive(state.readBuffer, 0, state.readBuffer.Length, 0, ReceiveCallBack, state);

            }
            catch (Exception ex)
            {

                Console.WriteLine("接收失败+" + ex.Message);
            }
        }

        #region 同步服务器


        //static void Main(string[] args)
        //{
        //    Socket socketListen = new Socket(AddressFamily.InterNetwork,SocketType.Stream,ProtocolType.Tcp);
        //    socketListen.Bind(new IPEndPoint(IPAddress.Any,8888));
        //    socketListen.Listen(0);
        //    Console.WriteLine("服务器启动成功");

        //    while (true)
        //    {
        //        Socket socketConnect = socketListen.Accept();
        //        Console.WriteLine("新客户端连接" );
        //        byte[] receiveBuffer = new byte[1024];
        //        int length = socketConnect.Receive(receiveBuffer);
        //        string receiveString = Encoding.Default.GetString(receiveBuffer,0,length);
        //        Console.WriteLine("收到数据："+ receiveString);

        //        byte[] sendBuffer = Encoding.Default.GetBytes(receiveString);
        //        socketConnect.Send(sendBuffer);


        //    }

        //}
        #endregion
    }
}