On 10/30/09 1:34 PM, Kyle Sluder said: >> Instead of a value transformer, in your NSManagedObject subclass add a >> new method called 'timelessDate' which returns a modified version of >> your 'date' attribute. Then bind your table to 'timelessDate' instead >> of 'date'. Also use keyPathsForValuesAffectingValueForKey to indicate >> that 'timelessDate' depends on 'date'. > >You could also model this as a transient property.
Yup. Yet I've never been too clear on what the pros and cons of these two approaches are. In seems in the OP's case, the user would never want to set this 'timelessDate' and so its really a real-only derived attribute. I *think* that in such cases, the approach I described is better. Also, transient properties participate in undo/redo, so I worry that strange things could happen there. In general, it will also depend how expensive it is to construct the derived property. Dates are fairly lightweight, so I doubt it matters here. -- ____________________________________________________________ Sean McBride, B. Eng [email protected] Rogue Research www.rogue-research.com Mac Software Developer Montréal, Québec, Canada _______________________________________________ Cocoa-dev mailing list ([email protected]) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to [email protected]
