removeObserver(_:forKeyPath:context:)
Raises an exception.
Declaration
func removeObserver(_ observer: NSObject, forKeyPath keyPath: String, context: UnsafeMutableRawPointer?)Parameters
- observer:
The object to remove as an observer.
- keyPath:
A key-path, relative to the set, for which
observeris registered to receive KVO change notifications. This value must not benil. - context:
Arbitrary data that is passed to
observerin Observevalue(forkeypath:of:change:context:).
Discussion
NSSet objects are not observable, so this method raises an exception when invoked on an NSSet object. Instead of observing a set, observe the unordered to-many relationship for which the set is the collection of related objects.