[Zope-dev] re: Subclassing ZObjectManager in ZClasses

[Daniel Rogahn]

re: http://lists.zope.org/pipermail/zope-dev/2000-March/004034.html
This message is about 1.5 years old, but no replies?, & I haven't seen any
similar messages or howtos?

--Alexandre Ratti  Fri, 31 Mar 2000
>Summary: (when creating a folderish ZClass and cascading base classes) if
>ZObjectManager isn't subclassed at 1st level, objects can be added to the
>folderish ZClass instances but they don't show in the manage_main object
list.

>Here I first created MyBaseClass, then I subclassed it together with
>ZObjectManager when creating MyTestClass
...
>when I add objects in an instance of MyTestClass they do not show
>in the object list (Content view). I *think* they are actually added
>because I cannot add an additional one with the same ID: I get an "ID
>already in use" error.

>It's not that bad, but I can't create a standard base class, then use it to
>create a folderish variant.

I have the same symptoms, objects dont display in a folder subclass, but are
there.
Heres how I fixed it:

Your base class must be the last in the class inheritance list.  You must
add all other base classes first.  This will almost always be a problem
because most base classes start with ZClass... and will be last
alphabetically.  (this will be much easier to fix if/when you can change, or
at least reorder, the base classes of an object)
eg: ZObject, ZObjectManager, CatalogAwareBase, MyBaseClass

If you have a complicated object, I think you can export it in XML, reorder
the base classes, & reimport.  But adding/removing classes this way doesn't
update the management interface tabs.

Daniel Rogahn
drogahn@d.umn.edu
http://www.d.umn.edu/~drogahn/