tcp communication between PDA and laptop

[C# Programming]

Hi!
I am new to c# mobile application programming subject. I want to implement simple client(on PDA)/server(on Laptop) application that converts lowercase letters that are sent by the client to uppercase letters and sends back to the client by the server.


socketForServer = new TcpClient();
socketForServer.Connect("ip address of laptop",port number);
textBox1.Text = "connected ";

socketForServer.SendTimeout = 50000;

networkStream = socketForServer.GetStream();
streamReader = new StreamReader(networkStream);
streamWriter = new StreamWriter(networkStream);

according to the given code the network stream stays null so I can not read or write anything to/from the server. could you help me how can I solve this problem ? or could you recommend me better solutions ?

thanks a lot.