On May 14, 2010, at 06:43, Richard Somers wrote: > Currently I track the selection using NSArrayController's selection methods. > I have a custom view that figures out what the selection should or should not > be and programatically sets the array controller's selection. It works very > well and is clean with not much code. Thus pushing the selection from the > view to the model is easy, just do it when the selection is pushed to the > array controller. > > However, pulling selection changes from the model back into the array > controller appears to be challenging. It would seem like bindings could help > out here somehow. NSArrayController works with bindings and so does Core > Data. Why can't I simply bind the "selectionIndexes" of the array controller > to the "selected" model attribute. I have tried this but I can't get the > proper bound to object and key path to work. Perhaps NSArrayController is not > designed to work in this fashion.
"Does not work" doesn't give us much to go on. If I understand you correctly, you're on the right track -- you want to bind the array controller's selection indexes to your data model's selection property. However, Core Data properties don't support index sets as a standard data type, so you have more work to do. Since NSIndexSet supports NSCoding, your easiest choice is probably to make your selection a transformable attribute. That means Core Data automatically converts the value to and from an archive using a standard transformer. An alternative would be to try using the undefined attribute type (but it has to be transient). Another alternative is a full-blown custom accessor implementation, which is kind of a PITA to get right. _______________________________________________ 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]
