// Examples for constructors that do not specify file permission.

// Create the NetworkStream for communicating with the remote host.
NetworkStream myNetworkStream;

if (networkStreamOwnsSocket){
     myNetworkStream = new NetworkStream(mySocket, true);          
}
else{
     myNetworkStream = new NetworkStream(mySocket);     
}

//引入命名空间
using System;
using System.IO;
using System.Net.Sockets ;

class MainClass
{
  public static void Main() 
  {
    TcpListener tcpl = new TcpListener(9999);
    tcpl.Start();

    for (;;)
    {
      Socket newSocket = tcpl.AcceptSocket();
      if (newSocket.Connected)
      {
        NetworkStream ns = new NetworkStream(newSocket);

        byte[] buf = {1,2,3,4,5,6,7,8,9};
        ns.Write(buf, 0, 9);

        ns.Flush();
        ns.Close();

      }
      newSocket.Close();
      break;

    }
  }

}