Re: Keys dependent on NSArrayController's selection
Re: Keys dependent on NSArrayController's selection
- Subject: Re: Keys dependent on NSArrayController's selection
- From: Dave Dribin <email@hidden>
- Date: Thu, 8 May 2008 01:53:01 -0500
On May 7, 2008, at 6:58 PM, Sean McBride wrote:
Have you put a breakpoint in 'canEnableButton'? When
'peopleController.selectionIndexes' changes, do you hit the
breakpoint?
I suspect not.
Nope. Well, it does get called once at app startup, but not as the
selection changes.
The docs for keyPathsForValuesAffectingValueForKey say
keyPaths are ok, but mmalc has mentioned on this list "provided that
the
path doesn't include to-many relationships". This appears to be
true in
your case, so probably explains it. The docs don't mention this
caveat. :(
I don't believe this falls under the to-many case. That would be
doing something like observing "arrangedObjects.firstName" to watch
when any first name in the array changes. That is not supported. You
have to observer every object in the array. For kicks, I did try
"peopleController.selectionIndex" as well as
"peopleController.selectedObjects" to no avail.
Also, I seem to remember reading that doing willChange/didChange
back-to-
back without actually changing anything is a no-no. You might check
the
archives to confirm my shoddy memory.
Unfortunately, my search foo must be weak. Searching on {will/
did}ChangeValueForKey turns up way to many hits.
-Dave
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