c# Socket通信异步TCP

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

 namespace ConsoleApplication2
 {
     public class StateObject
     {
         public Socket newsocket = null;
         public const int bufferSize = ;
         public byte[] buffer=new byte[bufferSize];
         public StringBuilder sb = new StringBuilder();

     }
     public class AsynchronousClient
     {
         private const int port = ;
         private static ManualResetEvent connectDone = new ManualResetEvent(false);
         private static ManualResetEvent sendDone = new ManualResetEvent(false);
         private static ManualResetEvent ReceiveDone = new ManualResetEvent(false);
         private static String response = String.Empty;

         public static void StartClient()
         {
             try
             {
                 IPAddress ipAddress = IPAddress.Parse("192.168.20.215");
                 IPEndPoint remoteEP = new IPEndPoint(ipAddress, port);
                 //生成一个TCP/IP socket
                 Socket client = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
                 //与目标终端连接
                 client.BeginConnect(remoteEP, new AsyncCallback(ConnectCallback), client);
                 //等待，直到连接程序完成。在ConnectCallback中适当位置有connecDone.Set()语句
                 connectDone.WaitOne();
                 byte[] b = new byte[] { 0x00, 0x00, 0x00, 0x29, 0x00, 0x00, 0x00, 0x13, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x01, 0x30, 0x00, 0x04 };
                 //发送数据
                 Send(client, b);
                 sendDone.WaitOne();
                 Receive(client);
                 ReceiveDone.WaitOne();
                 Console.WriteLine("Response{0}", response);
                 client.Shutdown(SocketShutdown.Both);
                 //Release the socket
                 client.Close();
                 Console.ReadLine();
             }
             catch (Exception e)
             {
                 Console.WriteLine(e.ToString());
             }
         }
         public static void ConnectCallback(IAsyncResult ar)
         {
             try
             {
                 //从state对象获取Socket
                 Socket client = (Socket)ar.AsyncState;
                //完成连接
                 client.EndConnect(ar);
                 Console.WriteLine("Socket connected to {0}", client.RemoteEndPoint.ToString());
                 connectDone.Set();
             }
             catch (Exception e)
             {
                 Console.WriteLine(e.ToString());
             }

         }
         private static void Receive(Socket client)
         {
             try
             {
                 //构造容器state
                 StateObject state = new StateObject();
                 state.newsocket = client;
                 //从远程目标接收数据
                 client.BeginReceive(state.buffer,,StateObject.bufferSize,,new AsyncCallback(ReceiveCallback),state);
             }
             catch(Exception e)
             {
                 Console.WriteLine(e.ToString());
             }
         }
         private static void ReceiveCallback(IAsyncResult ar)
         {
             try
             {
                 //从输入参数异步state对象中获取state和socket对象
                 StateObject state = (StateObject)ar.AsyncState;
                 Socket client = state.newsocket;
                 int bytesRead = client.EndReceive(ar);
                 if (bytesRead > )
                 {
                     //有数据存储
                     state.sb.Append(BitConverter.ToString(state.buffer, , bytesRead));
                    //继续读取
                     client.BeginReceive(state.buffer, , StateObject.bufferSize, , new AsyncCallback(ReceiveCallback), state);
                 }
                 else
                 {
                     //所有数据读取完毕
                     if (state.sb.Length > )
                     {
                         response = state.sb.ToString();
                     }
                     //所有数据读取完毕的指示信号
                     ReceiveDone.Set();
                 }
             }
             catch (Exception e)
             {
                 Console.WriteLine(e.ToString());
             }
         }
         private static void Send(Socket client, byte[] b)
         {
             //格式转换
             byte[] byteData = b;
             //开始发送数据到远程设备
             client.BeginSend(byteData,,byteData.Length,,new AsyncCallback(SendCallback),client);
         }
         private static void SendCallback(IAsyncResult ar)
         {
             try
             {
                 //从state对象中获取socket
                 Socket client = (Socket)ar.AsyncState;
                 //完成数据发送
                 int bytesSend = client.EndSend(ar);
                 Console.WriteLine("Send {0} bytes to sever",bytesSend);
                 //指示数据已经发送完成，主线程继续
                 sendDone.Set();
             }
             catch (Exception e)
             {
                 Console.WriteLine(e.ToString());
             }
         }
         public static int Main(string[] args)
         {
             StartClient();
             return ;
         }
     }
 }