Re: Behavior bind:toObject:withKeyPath:options:
Re: Behavior bind:toObject:withKeyPath:options:
- Subject: Re: Behavior bind:toObject:withKeyPath:options:
- From: mmalcolm crawford <email@hidden>
- Date: Fri, 23 Apr 2004 09:00:50 -0700
On Apr 23, 2004, at 7:34 AM, email@hidden wrote:
I have started using bind:toObject:withKeyPath:options: in a few
places in my code, and I was under the impression that:
[objB bind:@"nameB" toObject:self withKeyPath:@"nameA" options:nil];
would be a two-way link between the objects, i.e. if you modify nameA
then the change would propagate to nameB, and viceversa. In reality,
the previous call only updates nameB when nameA is changed.
Only by creating the binding in the other direction do I get what I
originally expected:
[self bind:@"nameA" toObject:objB withKeyPath:@"nameB" options:nil];
Is this the correct behavior and interpretation of the doc? Any advice
against having this use of bindings in one's code?
This will only work automatically if the object you bind (objB in your
example) is an instance of a subclass of NSController or NSView...
From: email@hidden
Subject: Re: NSObjectController and NSDefaultsController Binding?
Date: April 21, 2004 9:24:17 PM PDT
To: email@hidden
From Drafts from a few days ago...
On Apr 18, 2004, at 2:37 PM, Allan Odgaard wrote:
So in my example the model object (receiver of bind:...) had to be KVC
compliant for the key "title" and the controller had to be KVO
compliant for the key "values.title". No other requirements should
exist.
Not so.
The observer must also know to send a setValue:forKey: message to the
observed controller if and when the value associated with its (the
observer's) binding changes. For the model object in your example:
[model bind:@"title"
toObject:[NSUserDefaultsController sharedUserDefaultsController]
withKeyPath:@"values.title"
options:nil];
this is unlikely to be the case.
mmalc
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