using System.Net.Sockets;
using System.Net;
using System.IO;
using System.Threading;
public class ChatServer
{
private int port = 54321; //端口号
private IPAddress ip = IPAddress.Parse("10.20.30.40"); //ip地址
private TcpListener tcpListener= null;
private TcpClient tcpClient = null;
private NetworkStream networkStream = null;
private BinaryReader reader;
//private BinaryWriter writer;
private string getInfo = string.empty;
//开始监听
private void btnStartListen_Click(object sender, EventArgs e)
{
   tcpListener= new TcpListener( ip , port);
   tcpListener.Start(); //开始监听
   Thread acceptClientMsgThread= new Thread(AcceptClientMsg);
   //运行一个线程去处理客户端发来的信息
   acceptClientMsgThread.Start();
}
//处理客户端发来的信息
private void AcceptClientMsg()
 {
  tcpClient = tcpListener.AcceptTcpClient();
  if( tcpClient != null)
  {
    networkStream = tcpClient.GetStream();
    reader = new BinaryReader( networkStream);
    while (true){
     getInfo += reader.ReadString();  //读取客户端发来的信息
    }
  }
}
//假如还要显示信息的话,可以整个显示按钮(当然最好的办法是用些线程)
//然后点击button后让信息显示出来txtShowClientMsg.Text = getInfo;
//如果服务器端想再给客户端发信息,就可以整个发送按钮.然后添加如下代码
//string sendMsg = txtSendMsge.Text;
//writer = new BinaryWriter( networkStream);
//writer.write( sendMsg);
}

using System.Net.Sockets;
using System.Net;
using System.IO;
using System.Threading;
public class ChatClient
{
 private int port = 54321;
private IPAddress ip = IPAddress.Parse("10.20.30.40");
private TcpClient tcpClient = null;
private NetworkStream networkStream = null;
//private BinaryReader reader;
private BinaryWriter writer;
//连接server
private void btnStartConnect_Click(object sender, EventArgs e)
{
 tcpClient = new TcpClient();
 tcpClient.Connect( ip, port);
 networkStream = tcpClient.GetStream();
}
//发送信息
private void btnStartConnect_Click(object sender, EventArgs e)
{
 string sendMsg = txtSendMsg.Text;
 writer = new BinaryWriter( networkStream);
 writer.Write( sendMsg); //发送信息
}
//如果还要接受server的消息的话.
//reader = new BinaryReader( networkStream);
//string getInfo = reader.ReadString();
}