using System;
using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
namespace tcpserver
{
   ///  <summary> 
   /// Class1 的摘要说明。
   ///  </summary> 
   class server
  {
     ///  <summary> 
     /// 应用程序的主入口点。
     ///  </summary> 
    [STAThread]
     static  void Main( string [] args)
    {
       // 
       // TODO: 在此处添加代码以启动应用程序
       //
      int recv; // 用于表示客户端发送的信息长度
      byte [] data;// = new  byte [ 1024 ]; // 用于缓存客户端所发送的信息,通过socket传递的信息必须为字节数组 
      IPEndPoint ipep = new IPEndPoint(IPAddress.Any, 9050 ); // 本机预使用的IP和端口 
      Socket newsock = new Socket(AddressFamily.InterNetwork,SocketType.Stream,ProtocolType.Tcp);
      newsock.Bind(ipep); // 绑定
      newsock.Listen( 10 ); // 监听
      Console.WriteLine( " waiting for a client " );
      Socket client = newsock.Accept(); //当有可用的客户端连接尝试时执行，并返回一个新的socket,用于与客户端之间的通信 
      IPEndPoint clientip = (IPEndPoint)client.RemoteEndPoint;
      Console.WriteLine( " connect with client: " + clientip.Address + " at port: " + clientip.Port);
      string welcome = " welcome here! " ;
      data = Encoding.ASCII.GetBytes(welcome);
      client.Send(data,data.Length,SocketFlags.None); // 发送信息 
      while ( true )
      { // 用死循环来不断的从客户端获取信息 
        data = new  byte [ 1024 ];
        recv = client.Receive(data);
        Console.WriteLine( " recv= " + recv);
        if (recv == 0 ) // 当信息长度为0，说明客户端连接断开 
           break ;
        Console.WriteLine(Encoding.ASCII.GetString(data, 0 ,recv));
        client.Send(data,recv,SocketFlags.None);
      }
      Console.WriteLine( " Disconnected from " + clientip.Address);
      client.Close();
      newsock.Close();
    }
  }
}

using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
namespace tcpclient
{
  ///  <summary> 
  /// Class1 的摘要说明。
  ///  </summary> 
  class client
  {
    ///  <summary> 
    /// 应用程序的主入口点。
    ///  </summary> 
    [STAThread]
    static void Main(string[] args)
    {
      // 
      // TODO: 在此处添加代码以启动应用程序
      //
      byte[] data = new byte[1024];
      Socket newclient = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
      newclient.Bind(new IPEndPoint(IPAddress.Any, 905));
      Console.Write(" please input the server ip: ");
      string ipadd = Console.ReadLine();
      Console.WriteLine();
      Console.Write(" please input the server port: ");
      int port = Convert.ToInt32(Console.ReadLine());
      IPEndPoint ie = new IPEndPoint(IPAddress.Parse(ipadd), port); // 服务器的IP和端口
      try
      {
        // 因为客户端只是用来向特定的服务器发送信息，所以不需要绑定本机的IP和端口。不需要监听。 
        newclient.Connect(ie);
      }
      catch (SocketException e)
      {
        Console.WriteLine(" unable to connect to server ");
        Console.WriteLine(e.ToString());
        return;
      }
      int receivedDataLength = newclient.Receive(data);
      string stringdata = Encoding.ASCII.GetString(data, 0, receivedDataLength);
      Console.WriteLine(stringdata);
      while (true)
      {
        string input = Console.ReadLine();
        if (input == " exit ")
          break;
        newclient.Send(Encoding.ASCII.GetBytes(input));
        data = new byte[1024];
        receivedDataLength = newclient.Receive(data);
        stringdata = Encoding.ASCII.GetString(data, 0, receivedDataLength);
        Console.WriteLine(stringdata);
      }
      Console.WriteLine(" disconnect from sercer ");
      newclient.Shutdown(SocketShutdown.Both);
      newclient.Close();
    }
  }
}

while (true)  // 用死循环来不断的获取信息
{
  data = new byte[1024];
  recv = newclient.Receive(data);
 
  uiContext.Send(new SendOrPostCallback(
  state =>
  {
    int txtGetMsgLength = txtGetMsg.Text.Length;
    string recMsg = "Friend:    " + System.DateTime.Now.ToString() + "\n  " +Encoding.Unicode.GetString(data, 0, recv) + "\n";
    txtGetMsg.AppendText(recMsg);
    txtGetMsg.Select(txtGetMsgLength, recMsg.Length - Encoding.Unicode.GetString(data, 0, recv).Length - 1);
    txtGetMsg.SelectionColor = Color.Red;
  }), null);
}

private void btnSendMsg_Click(object sender, EventArgs e)
{
  string input = txtSendMsg.Text;
  if (input == "")
  {
    MessageBox.Show("消息不能为空!", "发送消息出错");
    txtSendMsg.Focus();
  }
  else
  {
    if (meIsClient)
    {
      newclient.Send(Encoding.Unicode.GetBytes(input));
      string showText = "Me:      " + System.DateTime.Now.ToString() + "\n  "
      + input + "\n";
      int txtGetMsgLength = txtGetMsg.Text.Length;
      txtGetMsg.AppendText(showText);
      txtGetMsg.Select(txtGetMsgLength, showText.Length - 1 - input.Length);
      txtGetMsg.SelectionColor = Color.Blue;
      txtSendMsg.Text = "";
    }
    else
    {
      client.Send(Encoding.Unicode.GetBytes(input));
      string showText = "Me    " + System.DateTime.Now.ToString() + "\n  "
      + input + "\n";
      int txtGetMsgLength = txtGetMsg.Text.Length;
      txtGetMsg.AppendText(showText);
      txtGetMsg.Select(txtGetMsgLength, showText.Length - 1 - input.Length);
      txtGetMsg.SelectionColor = Color.Blue;
      txtSendMsg.Text = "";
    }
  }
}