Controlling bindings with code

FROM : Trent Jacobs
DATE : Tue Mar 25 21:15:38 2008

The app I'm writing is centered around a particular list of objects 
(for example a list of items in a shop) with various filters allowed. 
it's a core data app and I'm using bindings wherever possible.

In the model I'm using I have an entity for my objects and I've set up 
relationships to the entities I'll be filtering on (for example brand, 
colour, whatever).

I've got everything with perfectly when I hook up the bindings in IB, 
i.e. when I select a brand the list of objects is filtered to only 
show objects of the selected brand. However, when I try to do the 
bindings in code it doesn't work.

To create the bindings I use:

       [myObjectController bind : @"contentSet"
                     toObject : filterController
                   withKeyPath : @"selection.objects"
                       options : nil];

where myObjectController and filterController are NSArrayController 
objects and selection.objects represents the relationship in the model.

This works fine. However, when I remove the contentset binding I would 
expect the filtering to be removed. This doesn't happen. What happens 
is that the list of objects stays the same although the controlling 
relationship to the filtering array controller is gone, i.e. I change 
brands and the list stays constant. To remove the bindings I am simply 
using:

       [myObjectController unbind : @"contentSet"];

I think this is happening because the NSArrayController is not being 
told to refresh but i can't find how to force a refresh.

Any ideas?

Thanks!