Socket listener = new Socket(AddressFamily.InterNetwork,      SocketType.Stream, ProtocolType.Tcp);

listener.Bind(localEndPoint);

//new IPEndPoint(IPAddress,port)//IPAdress.Parse("192.168.1.3")listener.Listen(100);

  listener.BeginAccept(          new AsyncCallback(AcceptCallback),          listener);

Socket handler = listener.EndAccept(ar);

handler.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,      new AsyncCallback(ReadCallback), state);

public class StateObject{  // Client socket.  public Socket workSocket = null;  // Size of receive buffer.  public const int BufferSize = 1024;  // Receive buffer.  public byte[] buffer = new byte[BufferSize];  // Received data string.  public StringBuilder sb = new StringBuilder();}

 // Read data from the client socket.     int bytesRead = handler.EndReceive(ar);

handler.BeginSend(byteData, 0, byteData.Length, 0,      new AsyncCallback(SendCallback), handler);

int bytesSent = handler.EndSend(ar);

    byte[] bytes = new Byte[1024];    IPAddress ipAddress = IPAddress.Parse("192.168.1.104");    IPEndPoint localEndPoint = new IPEndPoint(ipAddress, 11000);    // 生成一個TCP的socket    Socket listener = new Socket(AddressFamily.InterNetwork,      SocketType.Stream, ProtocolType.Tcp);    listener.Bind(localEndPoint);    listener.Listen(100);    while (true)    {      // Set the event to nonsignaled state.      allDone.Reset();      //開啟異步監聽socket      Console.WriteLine("Waiting for a connection");      listener.BeginAccept(           new AsyncCallback(AcceptCallback),           listener);      // 讓程序等待，直到連接任務完成。在AcceptCallback里的適當位置放置allDone.Set()語句.      allDone.WaitOne();      }  Console.WriteLine("/nPress ENTER to continue");  Console.Read();

  public static void AcceptCallback(IAsyncResult ar)  {    //添加此命令，讓主線程繼續.    allDone.Set();    // 獲取客戶請求的socket    Socket listener = (Socket)ar.AsyncState;    Socket handler = listener.EndAccept(ar);    // 造一個容器，并用于接收命令.    StateObject state = new StateObject();    state.workSocket = handler;    handler.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,      new AsyncCallback(ReadCallback), state);  }

  public static void ReadCallback(IAsyncResult ar)  {    String content = String.Empty;    // 從異步state對象中獲取state和socket對象.    StateObject state = (StateObject)ar.AsyncState;    Socket handler = state.workSocket;    // 從客戶socket讀取數據.     int bytesRead = handler.EndReceive(ar);    if (bytesRead > 0)    {      // 如果接收到數據，則存起來      state.sb.Append(Encoding.ASCII.GetString(state.buffer, 0, bytesRead));      // 檢查是否有結束標記，如果沒有則繼續讀取      content = state.sb.ToString();      if (content.IndexOf("<EOF>") > -1)      {        //所有數據讀取完畢.        Console.WriteLine("Read {0} bytes from socket. /n Data : {1}",          content.Length, content);        // 給客戶端響應.        Send(handler, content);      }      else      {        // 接收未完成，繼續接收.        handler.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,        new AsyncCallback(ReadCallback), state);      }    }  }

private static void Send(Socket handler, String data)  {    // 消息格式轉換.    byte[] byteData = Encoding.ASCII.GetBytes(data);    // 開始發送數據給遠程目標.    handler.BeginSend(byteData, 0, byteData.Length, 0,      new AsyncCallback(SendCallback), handler);  }private static void SendCallback(IAsyncResult ar)  {         // 從state對象獲取socket.      Socket handler = (Socket)ar.AsyncState;      //完成數據發送      int bytesSent = handler.EndSend(ar);      Console.WriteLine("Sent {0} bytes to client.", bytesSent);      handler.Shutdown(SocketShutdown.Both);      handler.Close();  }

  using System;  using System.Net;  using System.Net.Sockets;  using System.Text;  using System.Threading;    // State object for reading client data asynchronously  public class StateObject  {   // Client socket.   public Socket workSocket = null;   // Size of receive buffer.   public const int BufferSize = ;   // Receive buffer.   public byte[] buffer = new byte[BufferSize];   // Received data string.   public StringBuilder sb = new StringBuilder(); }  public class AsynchronousSocketListener {   // Thread signal.   public static ManualResetEvent allDone = new ManualResetEvent(false);    public AsynchronousSocketListener()   {   }    public static void StartListening()   {     // Data buffer for incoming data.     byte[] bytes = new Byte[];      // Establish the local endpoint for the socket.     // The DNS name of the computer     // running the listener is "host.contoso.com".     //IPHostEntry ipHostInfo = Dns.Resolve(Dns.GetHostName());     IPAddress ipAddress = IPAddress.Parse("...");      IPEndPoint localEndPoint = new IPEndPoint(ipAddress, );      // Create a TCP/IP socket.     Socket listener = new Socket(AddressFamily.InterNetwork,       SocketType.Stream, ProtocolType.Tcp);      // Bind the socket to the local endpoint and listen for incoming connections.     try     {       listener.Bind(localEndPoint);       listener.Listen();       while (true)       {         // Set the event to nonsignaled state.         allDone.Reset();          // Start an asynchronous socket to listen for connections.         Console.WriteLine("Waiting for a connection");         listener.BeginAccept(           new AsyncCallback(AcceptCallback),           listener);          // Wait until a connection is made before continuing.         allDone.WaitOne();       }     }     catch (Exception e)     {       Console.WriteLine(e.ToString());     }      Console.WriteLine("/nPress ENTER to continue");     Console.Read();   }    public static void AcceptCallback(IAsyncResult ar)   {     // Signal the main thread to continue.     allDone.Set();      // Get the socket that handles the client request.     Socket listener = (Socket)ar.AsyncState;     Socket handler = listener.EndAccept(ar);       // Create the state object.     StateObject state = new StateObject();     state.workSocket = handler;     handler.BeginReceive(state.buffer, , StateObject.BufferSize, , new AsyncCallback(ReadCallback), state);   }    public static void ReadCallback(IAsyncResult ar)   {     String content = String.Empty;         // Retrieve the state object and the handler socket     // from the asynchronous state object.     StateObject state = (StateObject)ar.AsyncState;     Socket handler = state.workSocket;      // Read data from the client socket.      int bytesRead = handler.EndReceive(ar);      if (bytesRead > )     {       // There might be more data, so store the data received so far.       state.sb.Append(Encoding.ASCII.GetString(         state.buffer, , bytesRead));        // Check for end-of-file tag. If it is not there, read        // more data.       content = state.sb.ToString();       if (content.IndexOf("<EOF>") > -)       {         // All the data has been read from the          // client. Display it on the console.         Console.WriteLine("Read {} bytes from socket. /n Data : {}",content.Length, content);          // Echo the data back to the client.         Send(handler, content);       }       else       {         // Not all data received. Get more.         handler.BeginReceive(state.buffer, , StateObject.BufferSize, , new AsyncCallback(ReadCallback), state);       }     }   }    private static void Send(Socket handler, String data)   {     // Convert the string data to byte data using ASCII encoding.     byte[] byteData = Encoding.ASCII.GetBytes(data);      // Begin sending the data to the remote device.     handler.BeginSend(byteData, , byteData.Length, ,       new AsyncCallback(SendCallback), handler);   }      private static void SendCallback(IAsyncResult ar)    {     try     {       // Retrieve the socket from the state object.       Socket handler = (Socket)ar.AsyncState;        // Complete sending the data to the remote device.       int bytesSent = handler.EndSend(ar);       Console.WriteLine("Sent {} bytes to client.", bytesSent);       handler.Shutdown(SocketShutdown.Both);       handler.Close();     }      catch (Exception e)      {       Console.WriteLine(e.ToString());     }   }    public static int Main(String[] args)    {     StartListening();     return ;   }  }