Hi, guys. Here's a question of the functionality like C++ copy constructor. I need to send the instance of a class, which was derived from Cutsom, to sub-rountines as parameter, and those routines will modify properities of the passed object. I don't want their changes affect the upper level program, so I need to pass the object by reference. Since the @ sign do nothing to an object, it seems the only way is to duplicate the existing object. i looked up all the manuals but found nothing can deal with this situation. It could be a common requirement, i think there must has solution somewhere. Thanks ahead.