Re: KVO Question -- Really Simple for Pros
Re: KVO Question -- Really Simple for Pros
- Subject: Re: KVO Question -- Really Simple for Pros
- From: "Alex Wait" <email@hidden>
- Date: Fri, 27 Jun 2008 23:29:28 -0700
I've read what you said but I don't know what to do still.
Do I need to implement the method? the -observeValueForKeyPath
>
> :ofObject:change:context: method?
I am not having trouble with bindings. They seem to be working ok.
What I need to know is what I need to add to get the text field to update
whenever firstName is changed. I want it to set
the value of its string value to the string.
If not, why not just do it in the action method? Would I do it the KVO
method so whenever I updated it, even outside of the message,
it would get updated? Also where do I put the -observeValueForKeyPath
>
> :ofObject:change:context: method?
>
"but how does the text field know what this means?" how do I tell it? that's
what I've been trying to ask all along.- Show quoted text -
On Fri, Jun 27, 2008 at 11:21 PM, Owen Yamauchi <
email@hidden <email@hidden>>
wrote:
> On Fri, Jun 27, 2008 at 10:20 PM, Alex Wait <email@hidden> wrote:
> > But I was sure since I have a firstName method and a setFirstName method
> it
> > would update the textField. I have used IB to bind the value of the
> > textField to the value of the person object and that works when I edit
> the
> > textfield (yay). So I know I have the proper methods. I think.
>
> If you've set the binding in IB, there's no need to write any code.
>
> The problem you're running into with this code is that you're
> registering the text field as an observer of changes in the firstName
> property, but the text field has no idea what it should do when it
> receives notification of changes. Changing firstName generates a KVO
> notification (two, actually) which causes a
> -observeValueForKeyPath:ofObject:change:context: message to be sent to
> the text field, but how does the text field know what this means? The
> obvious thing (to you) is to change its text, but there's any number
> of other things you can bind in a text field.
>
> If you want to set up the binding in code, use
> -bind:toObject:withKeyPath:options:.
>
> Owen
> [forgot to reply-all before]
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--
If you can't be kind, at least have the decency to be vague.
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