TcpListener listener =new TcpListener(new IPEndPoint(IPAddress.Parse(ip), port));//ip为服务器IP地址，port为监听的端口

Listener.Start();//开启监听

TcpClient remoteClient = listener.AcceptTcpClient();
//接收客户端 这里体现了同步的含义，如果客户端对该服务端发起连接的时候，程序在这里就会等待（阻塞），直到有客户端的连接请求为止

NetworkStream streamToClient = remoteClient.GetStream();

byte[] buffer = new byte[BufferSize]; // BufferSize为缓存的大小

 int bytesRead; 

 try

 {

  lock (streamToClient)//为了保证数据的完整性以及安全性 锁定数据流

   {

     bytesRead = streamToClient.Read(buffer, 0, BufferSize);

} 

lock (streamToClient)

           {

           streamToClient.Write(buffer, 0, buffer.Length);//buffer为发送的字符数组         

} 

streamToClient.Dispose();//释放数据流中的数据

 remoteClient.Close();//释放TcpClient实例 

TcpClient tcp = new TcpClient();

tcp.Connect(IP,Port);//根据服务器的IP地址和侦听的端口连接

if (tcp.Connected)

{

//连接成功的消息机制 详细见DEMO

ShowGetData("成功连接上了服务器：", this.strIP.Text.ToString());
 

 } 

NetworkStream streamToServer = tcp.GetStream(); 

//发送字符串

byte[] buffer = Encoding.Unicode.GetBytes(msg); //msg为发送的字符串  

 try

     {

       lock (streamToServer)
      {

      streamToServer.Write(buffer, 0, buffer.Length);   // 发往服务器

       }

     //接收字符串
       buffer = new byte[BufferSize];
       lock (streamToServer)

      {

        bytesRead = streamToServer.Read(buffer, 0, BufferSize);

      }

} 

private TcpListener listener;        //监听类

listener = new TcpListener(new IPEndPoint(IPAddress.Parse(ip), port));

listener.Start();//开启侦听，对连接的客户端的数目没有限制

listener.Start(int i);// 开启侦听，最多只能连接i个客户端数目 

     /// <summary>

    /// 接收回调函数

    /// </summary>

    /// <param name="ar"></param>

    private void clientConnect(IAsyncResult ar)

    {

    try

      {
        TcpListener listener = (TcpListener)ar.AsyncState;
        //接受客户的连接,得到连接的Socket
        Socket client = listener.EndAcceptSocket(ar);

      }

      catch { }

    } 

/// <summary> 

/// 异步接收数据

 /// </summary>

 private void receiveData(Socket client)

{

   // 调用异步方法 BeginReceive 来告知 socket 如何接收数据
  IAsyncResult iar = client.BeginReceive(buffer, 0, BagSize, SocketFlags.None, out errorCode, receiveCallback, buffer);

      }

   }

    /// <summary>

    /// 接收数据回调函数

    /// </summary> 

    /// <param name="ar"></param>

    private void receiveCallback(IAsyncResult ar)

    {     
        //接收到的数据长度．
        int receLen = 0;

        try

        {
          receLen = client.EndReceive(ar, out errorCode);        

if (receLen > 0)

         {
           OnReceiveData(client);//接收到数据之后的处理函数

          }
        }
       catch {   }

      }
      else { }

    } 

/// <summary>

/// 异步发送报文
/// </summary>

 /// <param name="data"></param>
 private void OnReceiveData (Socket socket)

{
     string strLogin = “succeed recived”;

byte[] data = Encoding.ASCII.GetBytes(strLogin);

 socket.BeginSend(data, 0, data.Length, SocketFlags.None, out errorCode, sendCallBack, socket);//异步发送数据

     }

      else

      { }

    }

/// <summary>

 /// 异步发送回调事件

 /// </summary>

 /// <param name="ar"></param>

private void sendCallBack(IAsyncResult ar)

    {

socket.EndSend(ar, out errorCode);

     } 

private TcpClient tcpcz = null

 tcpcz = new TcpClient()

 tcpcz.BeginConnect(ipaddress, Convert.ToInt32(port), new AsyncCallback(ConnectCallback), tcpcz);//根据服务器的IP地址和端口号 异步连接服务器

 /// <summary>

/// 异步连接的回调函数

 /// </summary>

 /// <param name="ar"></param>

 private void ConnectCallback(IAsyncResult ar)

    {

      TcpClient t = (TcpClient)ar.AsyncState;

      try

      {

        if (t.Connected)

        {

          t.EndConnect(ar);//函数运行到这里就说明连接成功

        }

        else

        {

        }

      }

      catch () {  }

    } 

NetworkStream stream = tcp.GetStream();//创建于服务器连接的数据流

        //发送字符串

  string strLogin = “this is socket example”;

  byte[] data = Encoding.ASCII.GetBytes(strLogin);

 stream.BeginWrite(data, 0, data.Length, new AsyncCallback(SendCallback),stream);//异步发送数据

 //接收字符串

  byte[] result = new byte[tcp.Available]; // tcp.Available为接受的字符串大小

  try

 {

   stream.BeginRead(result, 0, result.Length, new AsyncCallback(ReadCallback), stream);//异步接受服务器回报的字符串

  }

    catch { }

    string strResponse = Encoding.ASCII.GetString(result).Trim();//从服务器接受到的字符串

 }

  }

     catch ()

     {

     }

   }