problem retrieving data processed by class library

 
Pls help! how am i going to update a form's listbox with data handled and stored by a class library ( the messages are  from a connected socket)?
I want this listbox to diplay chat messages.


class X (class library code)

properties: ipadd,port,isconnected...etc
methods:
    Connect()  and  ConnectCallback //will establish connection to the socket using BeginConnect and EndConnect
    WaitForData and OnDataReceived(Callback) //will received the messages using BeginReceive and EndReceive
 

        public void WaitForData()
        {
            recieveCallback = new AsyncCallback(onDataReceived);
            StateObject socket = new StateObject();
  & ...