[Zope3-Users] How to extend File?

[John Toews]

Hi all,

I'm trying to do something I thought would be very simple. I think I
don't understand the Component Architecture well enough...

I want to take the base File and simply add a property to it (a string
representing a guid). That's all, everything else would remain the same.
I've tried a couple different ways of doing:

class IContentGuid(Interface):
	guid = TextLine(title=_('guid desc'))

class ContentBase(File):
	zope.interface.implements(IContentGuid)

And various configure.zcml setups. I can't really explain what's going
wrong either. The best I've gotten is a link in the ZMI to ContentBase,
which when clicked on will add an item, but after typing in a name and
hitting Apply, a system error occurs. I think I'm just on the wrong
track.

Any ideas on what (all) I'm doing wrong?
Thanks!
John