Re: Core Data to-many relationships and keyPathsForValuesAffectingValueForKey

FROM : Sean McBride
DATE : Fri Nov 23 18:29:06 2007

On 11/23/07 11:48 AM, <email_removed> said:

>I know in 10.4 it wasn't ever possible as the method
>setKeys:triggerChangeNotificationsForDependentKey: didn't work with
>keyPaths but
>I suppose I should be able to do it in 10.5 with
>keyPathsForValuesAffectingValueForKey.
>
>I implemented method keyPathsForValuesAffectingValueForKey in Account.m as
>follows :
>- (NSSet *)keyPathsForValuesAffectingValueForKey:(NSString *)key {
>  NSMutableSet *keyPaths = [NSMutableSet setWithSet:[super
>keyPathsForValuesAffectingValueForKey:key]];
>  if ([key isEqualToString:@"total"]) {
>      [keyPaths addObject:@"operations.amount"];
>  }
>  return keyPaths;
>}
>
>When trying to run my program, I get an error saying that
>_NSFaultingMutableSet
>is not KVO compliant with key "amount".


I have also switched my code to use this new
keyPathsForValuesAffectingValueForKey method.  I have not been able to
make it work with key paths either.  I don't get the error you do, since
I'm not using Core Data.  It just silently fails.  My code is slightly
different (I don't always create a new set), but I doubt that accounts
for it.  Anyway, here's how I do it:

+ (NSSet*)keyPathsForValuesAffectingValueForKey:(NSString*)key
{
   NSSet* set = [super keyPathsForValuesAffectingValueForKey:key];
   if ([key isEqualToString:@"overallStatus"]) {
       set = [set setByAddingObjectsFromSet:[NSSet setWithObjects:
           @"subStatus1", @"subStatus2",
  @"someController.subStatus3", (id)nil]];
   }
   return set;
}

It works for subStatus1 and 2, but not 3.

Anyone have working keyPathsForValuesAffectingValueForKey sample code?

--
____________________________________________________________
Sean McBride, B. Eng                <email_removed>
Rogue Research                        www.rogue-research.com
Mac Software Developer              Montréal, Québec, Canada