Type Method

setKeys:triggerChangeNotificationsForDependentKey:

Configures the observed object to post change notifications for a given property if any of the properties specified in a given array changes.

Declaration

+ (void)setKeys:(NSArray *)keys triggerChangeNotificationsForDependentKey:(NSString *)dependentKey;

Parameters

keys

The names of the properties upon which the value of the property identified by dependentKey depends.

dependentKey

The name of a property whose value depends on the properties specified by keys.

Discussion

Invocations of will- and did-change KVO notification methods for any key in keys automatically invokes the corresponding change notification methods for dependentKey. The observed object does not receive willChange or didChange messages to generate the notifications.

Dependencies should be registered before any instances of the receiving class are created, so you typically invoke this method in a class's initialize method, as illustrated in the following example.

+ (void)initialize {
    [self setKeys:@[@"firstName", @"lastName"] triggerChangeNotificationsForDependentKey:@"fullName"];
}

See Also

Observing Customization

+ automaticallyNotifiesObserversForKey:

Returns a Boolean value that indicates whether the observed object supports automatic key-value observation for the given key.

+ keyPathsForValuesAffectingValueForKey:

Returns a set of key paths for properties whose values affect the value of the specified key.

observationInfo

Returns a pointer that identifies information about all of the observers that are registered with the observed object.