Tutor.com Classroom How-To #3: specifying "End-Of-Message" to a TCP/IP listener

These How-To tips are taken from The Tutor.com Classroom: Architecture and techniques using Silverlight, WPF, and the Microsoft .NET Framework.

You can check out the Silverlight Tutor.com Classroom in "practice" mode, although the real experience is with a live tutor on the other side!

Since a TCP/IP Listener is constantly in a listening state, the Listener needs to know when to act on the bytes received. To accomplish this, listen first for 8 ASCII bytes that represent two 32-bit integers specifying the number of bytes the sender is sending, and then continue listening until receiving this number of bytes. This is an easier solution to implement than using a delimiter to specify end-of-message, since you don’t have to worry about delimiter escaping, and since you can specify the exact number of bytes to listen for via the third parameter to SocketAsyncEventArgs.SetBuffer().

Tutor.com Classroom How-To #2: connecting to a TCP/IP Listener

These How-To tips are taken from The Tutor.com Classroom: Architecture and techniques using Silverlight, WPF, and the Microsoft .NET Framework.

You can check out the Silverlight Tutor.com Classroom in "practice" mode, although the real experience is with a live tutor on the other side!

Using the Socket class, we just need to create a SocketAsyncEventArgs and call ConnectAsync(). Notice an example of the “#if WPF” directive for subtle Silverlight/WPF differences (as described in the "Code Sharing" post) when we set the SocketAsyncEventArgs RemoteEndPoint.

public void Connect(string host, int port)
{
  //instantiate socket
  m_Socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);

  //set up endpoint
#if WPF
    m_SocketSendArgs.RemoteEndPoint = new IPEndPoint(Dns.GetHostAddresses(host)[0], port);
#else
    m_SocketSendArgs.RemoteEndPoint = new DnsEndPoint(host, port);
#endif

  //set up args
  SocketAsyncEventArgs args = new SocketAsyncEventArgs();

  args.UserToken = m_Socket;
  args.RemoteEndPoint = m_SocketSendArgs.RemoteEndPoint;
  args.Completed += new EventHandler(OnConnect);

  m_Socket.ConnectAsync(args);
}