C# socket异步通讯

Server：

using System;
using System.Net;
using System.Net.Sockets;
using System.Text;

namespace TCP_Server
{
    internal class Program
    {
        private static readonly byte[] Buffer = new byte[1024];
        private static int _count;

        private static void Main()
        {
            WriteLine("Server is ready.", ConsoleColor.Green);

            //①创建一个新的Socket,这里我们使用最常用的基于TCP的Stream Socket（流式套接字）
            var socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);

            //②将该socket绑定到主机上面的某个端口
            //方法参考：http://msdn.microsoft.com/zh-cn/library/system.net.sockets.socket.bind.aspx
            socket.Bind(new IPEndPoint(IPAddress.Any, 7788));

            //③启动监听，并且设置一个最大的队列长度
            //方法参考：http://msdn.microsoft.com/zh-cn/library/system.net.sockets.socket.listen(v=VS.100).aspx
            socket.Listen(3);

            //④开始接受客户端连接请求
            //方法参考：http://msdn.microsoft.com/zh-cn/library/system.net.sockets.socket.beginaccept.aspx
            socket.BeginAccept(new AsyncCallback(ClientAccepted), socket);
            Console.ReadLine();
        }

        // 客户端连接成功
        public static void ClientAccepted(IAsyncResult ar)
        {
            //设置计数器
            _count++;
            var socket = ar.AsyncState as Socket;
            //这就是客户端的Socket实例，我们后续可以将其保存起来
            if (socket != null)
            {
                var client = socket.EndAccept(ar);
                
                //客户端IP地址和端口信息
                IPEndPoint clientipe = (IPEndPoint)client.RemoteEndPoint;

                WriteLine(clientipe + " is connected，total connects " + _count, ConsoleColor.Yellow);

                //接收客户端的消息
                client.BeginReceive(Buffer, 0, Buffer.Length, SocketFlags.None, new AsyncCallback(ReceiveMessage), client);
            }

            //准备接受下一个客户端连接请求
            if (socket != null) socket.BeginAccept(new AsyncCallback(ClientAccepted), socket);
        }

        // 接收客户端的信息
        public static void ReceiveMessage(IAsyncResult ar)
        {
            var socket = ar.AsyncState as Socket;
            //客户端IP地址和端口信息
            if (socket != null)
            {
                IPEndPoint clientipe = (IPEndPoint)socket.RemoteEndPoint;
                try
                {
                    //方法参考：http://msdn.microsoft.com/zh-cn/library/system.net.sockets.socket.endreceive.aspx
                    var length = socket.EndReceive(ar);
                    //读取出来消息内容
                    var message = Encoding.UTF8.GetString(Buffer, 0, length);
                    //输出接收信息
                    WriteLine(clientipe + " ：" + message, ConsoleColor.White);
                    //服务器发送消息
                    socket.Send(Encoding.UTF8.GetBytes("Server received data"));
                    //接收下一个消息
                    socket.BeginReceive(Buffer, 0, Buffer.Length, SocketFlags.None, new AsyncCallback(ReceiveMessage), socket);
                }
                catch (Exception)
                {
                    //设置计数器
                    _count--;
                    //断开连接
                    WriteLine(clientipe + " is disconnected，total connects " + (_count), ConsoleColor.Red);
                }
            }
        }

        public static void WriteLine(string str, ConsoleColor color)
        {
            Console.ForegroundColor = color;
            Console.WriteLine("[{0:MM-dd HH:mm:ss}] {1}", DateTime.Now, str);
        }
    }
}

　　Client：

using System;
using System.Net.Sockets;
using System.Text;

namespace TCP_Client
{
    internal class Program
    {
        private static readonly byte[] Buffer = new byte[1024];

        private static void Main()
        {
            try
            {
                //①创建一个Socket
                var socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);

                //②连接到指定服务器的指定端口
                socket.Connect("127.0.0.1", 7788);

                WriteLine("Client: Connect to server success!", ConsoleColor.White);

                //③实现异步接受消息的方法 客户端不断监听消息
                socket.BeginReceive(Buffer, 0, Buffer.Length, SocketFlags.None, new AsyncCallback(ReceiveMessage), socket);

                //④接受用户输入，将消息发送给服务器端
                while (true)
                {
                    var message = Console.ReadLine();
                    if (message != null)
                    {
                        var outputBuffer = Encoding.UTF8.GetBytes(message);
                        socket.BeginSend(outputBuffer, 0, outputBuffer.Length, SocketFlags.None, null, null);
                    }
                }
            }
            catch (Exception ex)
            {
                WriteLine("Client: Error " + ex.Message, ConsoleColor.Red);
            }
            finally
            {
                Console.Read();
            }
        }

        // 接收信息
        public static void ReceiveMessage(IAsyncResult ar)
        {
            try
            {
                var socket = ar.AsyncState as Socket;

                //方法参考：http://msdn.microsoft.com/zh-cn/library/system.net.sockets.socket.endreceive.aspx
                if (socket != null)
                {
                    var length = socket.EndReceive(ar);
                    var message = Encoding.ASCII.GetString(Buffer, 0, length);
                    WriteLine(message, ConsoleColor.White);
                }

                //接收下一个消息
                if (socket != null)
                {
                    socket.BeginReceive(Buffer, 0, Buffer.Length, SocketFlags.None, new AsyncCallback(ReceiveMessage), socket);
                }
            }
            catch (Exception ex)
            {
                WriteLine(ex.Message, ConsoleColor.Red);
            }
        }

        public static void WriteLine(string str, ConsoleColor color)
        {
            Console.ForegroundColor = color;
            Console.WriteLine("[{0:MM-dd HH:mm:ss}] {1}", DateTime.Now, str);
        }
    }
}