Re: _NSKeyValueObservationInfoCreateByRemoving crashing
Re: _NSKeyValueObservationInfoCreateByRemoving crashing
- Subject: Re: _NSKeyValueObservationInfoCreateByRemoving crashing
- From: Stefan Fisk <email@hidden>
- Date: Tue, 1 Nov 2005 20:41:25 +0100
I do see your point, but I'm not quite sure why i shouldn't be able
to return a copy. But I am experiencing the exact same problem with
the result class's other key - 'properties' - which internally is a
mutable dictionary. From what i understand KVO should do the hard
work for you, so that if any object in the observed key path changes
you get notified properly anyway. If that is not the case i can
understand fully why my code crashes.
The reason why I want to copy the engines is that you can make them
perform commands, the result of which gets returned through
notifications. I've tried various schemes to enable only one engine
instance perform commands for several 'clients', but it's nowhere as
clean as it could be if i was allowed to sprinkle copies wherever i
felt like it.
A possible solution would be to just store the engine's path in the
result, and then create a value transformer that converted it into
the engine's localized name, but I'm not prepared to resort to such
solutions until I understand why I'd have to.
1 nov 2005 kl. 19.20 skrev mmalcolm crawford:
On Nov 1, 2005, at 9:26 AM, Stefan Fisk wrote:
The Engine class only has one instance variable that identifies
it, so the copyWithZone: just calls initWithPath:.
I'd *guess* that by returning a copy in the accessor you're
subverting KVO and bindings in general, since the object being
observed isn't the same as the property of the original (and it's
continually changing with each access).
It's not clear why you would return a copy of an Engine -- from the
name it sounds like something that would be a relationship rather
than an attribute...?
mmalc
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