Le 30 janv. 09 à 20:14, Jean-Nicolas Jolivet a écrit :
I've been working on my first CoreData project and I have a question
regarding dynamically generated accessors for to-many relationships
and KVC...
I'll keep it as simple as possible, let's assume I have a Department
entity which contains many Employees entities....
from what I understand in the doc, CoreData should automatically
generate those methods for Department:
-addEmployees:(NSSet *)values
-addEmployeesObject:(NSManagedObject *)value
My question is, how would I access these 2 methods using KVC
accessors?
For example, if I want to set the employee's name attribute I can
use: [anEmployee setValue:@"John Doe" forKey:@"name"];
Following this pattern, could I use
[aDeparment setValue:anEmployee forKey@"employees]; // Assuming
anEmployee is an NSManagedObject*
or
[aDeparment setValue:someEmployees forKey@"employees]; // Assuming
someEmployees is an NSSet*
In other words, are relationship also KVC and, will CoreData
aumatically call the correct method depending on the type of the
"value" I'm setting (either an NSSet or an NSManagedObject) ?
No. I never tried, but I'm pretty sure you will obtain garbage, at
least for you first proposition. The second will simply replace the
old employees set with someEmployees.
I know I can declare an NSManagedObject category with a bunch of
accessors etc.. to suppress compiler warning but I was wondering
about the KVC get/set as I am using them too....
If you want to use the KVC method use -mutableSetValueForKey or -
mutableSetValueForKeyPath: . In return you have a proxy object for the
key (keypath). Send to this proxy usual mutable set methods, the KVO
notifications will be send for you. EX :
[[aDepartment mutableSetForKey:@"employees"] addObject:someEmployees];
[[aDepartment mutableSetForKey:@"employees"] unionSet:someEmployees];
Frédéric
_______________________________________________
Cocoa-dev mailing list (Cocoa-dev@lists.apple.com)
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 arch...@mail-archive.com
