Re: How to set up manual bindings
Re: How to set up manual bindings
- Subject: Re: How to set up manual bindings
- From: Scott Anguish <email@hidden>
- Date: Fri, 13 Feb 2004 11:01:32 -0800
On Feb 13, 2004, at 4:49 AM, Reni Puls wrote:
You have to admit, though, that the new Controller Layer has been the
source of a lot of confusion since it was introduced. It's very easy
to get excited about the cool new things you can do with bindings and
KVO, and this naturally leads to frustration when you find out that it
doesn't quite work as you had expected.
Well, certainly there are multiple reasons for that, not the least of
which is that it's a bit of a new way of thinking.
If you simply want to ensure that two values are kept in sync without
a controller, you are encouraged to use key-value observing.
<http://cocoa.mamasam.com/COCOADEV/2004/02/1/83965.php>
... effectively re-implementing something that (I thought) bindings
already do.
No, not really.
KVO is used by the controllers, and by bindings, but you're not really
needing to re-implement anything.
To be a controller in the bindings sense, you need to implement
NSEditorRegistration, and the bindable object NSEditor. Those
protocols control when the data is set, and related things like that.
You can't bind two objects directly without supporting those
protocols. The UI items support one side, and the NSController
supports the other.
KVO is actually the answer for your issue. and with automatic
observing, you don't need to implement one side.. just register and
observe
I just want to understand *why* Apple chose to make bindings one-way
only. No blame, no bad feelings. Simple, pure curiosity. :-)
They're not.. they just need the appropriate protocols, and usually
those require a controller to implement them. :-)
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