At 01:57 06/07/99 , Michael Bernstein wrote:

I've been playing around with Zclasses for awhile, but have reached a bit of a stumbling block.

I want to create a set of Zclasses that can only be contained within certain other Zclasses. An arbitrary example would be a 'book' object that can only be created inside a 'shelf' object.

Create the 'shelf' object with ObjectManager as a base class. Now, on the Methods tab, create the 'book' ZClass (including the factory object, and the creation form and method). It now will automatically be included in the Add list of the shelf object.

I also would like to add a property to a ZClass that is a pointer to an instance of another ZClass of a certain type. An arbitrary example would be a 'Book' ZClass that has an 'Author' property that points to an instance of an 'Author' ZClass.

You can't create a property of an arbitrary object type on ZClasses. You can treat the author class the same way you did with the book class, derive the Book class from ObjectManager, and create your author ZClass on its methods tab. If the author ZClass should be accessible in other places as well, you should create it at product level and include in the 'Subobjects' tab of the book class. Note, that to the end user, your book never has to look like a folderish object. If you unselect the 'Objects should appear in folder lists?' option on the 'Subobjects' tab, your ObjectManager derived ZClass will look like any other simple class. However, it is now possible to contain one or more 'author' instances in your 'book' instance. -- Martijn Pieters, Web Developer | Antraciet http://www.antraciet.nl | Tel: +31-35-7502100 Fax: +31-35-7502111 | mailto:mj@antraciet.nl http://www.antraciet.nl/~mj | PGP: http://wwwkeys.nl.pgp.net:11371/pks/lookup?op=get&search=0xA8A32149 ------------------------------------------