How to write a value validation method for core data?
- by mystify
The docs say:
you should implement methods of the
form validate:error:, as defined by the NSKeyValueCoding protocol
so lets say I have an attribute which is an int: friendAge
I want to make sure that any friend may not be younger than 30. So how would I make that validation method?
-validateFriendAge:error:
What am I gonna do in there, exactly? And what shall I do with that NSError I get passed? I think it has an dictionary where I can return a humanly readable string in an arbitrary language (i.e. the one that's used currently), so I can output a reasonable error like: "Friend is not old enough"... how to do that?