Subclassing NSManagedObject
Subclassing NSManagedObject
- Subject: Subclassing NSManagedObject
- From: Michael Grützner <email@hidden>
- Date: Mon, 31 Dec 2007 11:46:49 +0100
Hi List,
I have created a class MyEntity which is a subclass of
NSManagedObject. The Entity contains
one attribute ("name") and one to-many relationship ("myRelation").
In MyEntity I override the following two methods and I have one
initWithName: method:
- (id) valueForKey:(NSString *)key; {
return [super valueForKey:key];
}
- (void) setValue: (id)value forKey: (NSString *)key {
[super setValue:value forKey:key];
}
- (id) initWithName: (NSString *) newName {
self = [super init];
if(self)
[self setValue:newName forKey:@"name"];
return self;
}
Then I try to add an instance of MyEntity to an NSArrayController via
addObject: with the code:
MyEntity *entity = [[MyEntity alloc] initWithName:@"My Name"];
[super addObject:entity];
While adding the object to the NSArrayController I get the following
exception:
[<MyEntity 0x183310> setValue:forUndefinedKey:]: the entity (null) is
not key value coding-compliant for the key name.
What is the reason for the exception? Do I have to add custom accessor
methods to MyEntity? If yes, how might these methods
look like for a to-many relationship?
Thank you very much in advance,
Michael
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