Re: NSTableView column bindings and "deep" key paths
Re: NSTableView column bindings and "deep" key paths
- Subject: Re: NSTableView column bindings and "deep" key paths
- From: Keary Suska <email@hidden>
- Date: Fri, 15 Jan 2010 08:59:38 -0700
On Jan 14, 2010, at 9:47 AM, Gerd Knops wrote:
> I have a typical NSTableView setup where the column content is provided by an NSArrayController.
>
> Now say a column is bound to arrayController.arrangedObjects key path a.b.c.d.
>
> In this scenario if "b" changes (even in a KVO-complient way), it will still result in an NSInternalInconsistencyException 'Cannot remove an observer xxx for the key path "c.d" from <old instance of "b">, most likely because the value for the key "c" has changed without an appropriate KVO notification being sent.'
>
> I understand why this is happening (nothing is observing changes of "b", so the actual observer is left "dangling").
>
> The question is how can I change my design to avoid this situation?
The most common reason I have found for this error is that multiple KVO notifications are being sent for the same change. I.e., if you have a willChnage/didChange pair inside or around a KVO compliant setter.
HTH,
Keary Suska
Esoteritech, Inc.
"Demystifying technology for your home or business"
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