I need help in understanding messaging better in C++/MFC version 6. I understand I can use SendMessage( ...) and TranslateMessage(....) commands, but don't fully comprehend how to utilize them. I am not sure about WParam and LParam's parameters. I've read the MSCN help files on it, but don't get enough examples or a simpler explanation than I can understand. Really need a short primer on sending and reading messages. Is there a primer on the web someplace? What I want to do is send a message to a List Box. I have 3 List Boxes and for one of them I want to send a message(not a flag) not to use negative numbers.