What is wrong with BeginReceive?

[sameh serag]

Hi all,
I have a problem with .NET sockets...
The code snippet bellow was working fine with .NET 2.0. After I installed .NET 3.0 it didn't work properly.

private static void BeginReceiving()
        {
            //client is an instance of 'Socket'
            try
            {
                Monitor.Enter(client);
                // Create the state object.
                StateObject state = new StateObject();
 
                // Begin receiving the data from the remote server.
                client.BeginReceive(state.buffer, 0, StateObject.BUFFER_SIZE, SocketFlags.None/*0*/,
                    new AsyncCallback(ContinueReceiving), state);
            }
 
            catch (System.Exception ex)
            {
                      //code clipped
            }
            finally
            {
                if (client != null) Monitor.Exit(client);
            }
        }
//---------------------------------------------------------------------
        private static void ContinueReceiving(IAsyncResult ar)
        {
            try
            {
                // Retrieve the state object from the asynchronous state object.
                StateObject state = (StateObject)ar.AsyncState;
 
                // Read data from the remote device.
                int bytesRead = client.EndReceive(ar);
                if (bytesRead > 0)
                {
                    //
                    // There might be more data, so store the data received so far.
                               state.reveivedData.Append(Encoding.ASCII.GetString(state.buffer, 0, bytesRead));
//ETX is a pre-defined constant -- by it, I know I've received a complete message from the server
                    if (state.reveivedData.ToString().IndexOf(Globals.ETX) > -1)//I reached the end of sent data
                    {
 
                       //start parsing the message
                       //code clipped
 
                    }
                    else //there still more data in the current message received from the server
                    {
                        // Get the rest of the data.
/*THE EXTREME BEHAVIOR HAPPENS HERE */
                        client.BeginReceive(state.buffer, 0, StateObject.BUFFER_SIZE,  SocketFlags.None/*0*/,
                            new AsyncCallback(ContinueReceiving), state);
                    }
                }
            }
            catch (System.Exception ex)
            {
                //code clipped
            }
            finally
            {
            }
        }
//--------------------------------------------------------------
// State object for receiving data from server.
public class StateObject
{
    // Size of receive buffer.
    public const int BUFFER_SIZE = 256;
    // Receiving buffer.
    public byte[] buffer = new byte[BUFFER_SIZE];
    // Received data string.
    public StringBuilder reveivedData = new StringBuilder();
}
 

- when the message is smaller the BUFFER_SIZE, it works properly
- The problem happens when the message's length is greater than the BUFFER_SIZE. When I debugged the code I found that the code doesn't work properly when I want to receive more data to complete the message (i.e. I am waiting for the ETX). In this case I send the state object [which contains the data received so far] with the AsyncCallback to appending more data to it.
Unfortunately, reveivedData (which is a StringBuilder member in the StateObject to concatenate data received in it) found empty the next cycle i received data (although it was working properly when I was installing .NET 2.0 only)

-------------------------------------
Any help will be greatly appreciated...
thanks in advance