Re: KVO Response for incomplete paths

FROM : Gordon Apple
DATE : Wed May 21 23:15:23 2008

So what you are saying (if I understand it correctly) is that once you
try to observe the property at that path, the intercept mechanism for the
property set-accessor is actually put into place, along with its
before/after notifications, and will notify properly when the path is
actually viable.  That is good news. So I should be able to rule that out
and look elsewhere for problems I am encountering.

> On 21 May 2008, at 19:51, Gordon Apple wrote:
>

>>    OK, thanks.  That helps on the KVO responses.  However, I have
>> other
>> questions about the entire KVO process.
>>
>>    Not having access to the innards of KVO, I wonder how dymanic the
>> process is.  For example, my inspector bindings are through an object
>> controller which binds through MSApp.mainWindow which seems to
>> successfully
>> switch its focus to a new main window with no problems.  This, to me,
>> indicates that the process operates dynamically according to the path,
>> rather than statically binding when it is set up.
>>
>>    So my new question is whether or not I can successfully observe a
>> property that does not exist at registration time, and then have it
>> observe
>> properly when the path is created.  E.g., register to observe
>> xxx.shadow.angle when shadow does not exist, then add the shadow
>> object and
>> have xxx.shadow.angle be observed properly.

>
> As long as xxx returns nil for -valueForKey:@"shadow" initially, and
> then puts out proper KVO notifications when a shadow comes into being,
> this works just fine.
>
> Mike.
>