Re: No validation with a bound NSTableView and custom NSFormatter
Re: No validation with a bound NSTableView and custom NSFormatter
- Subject: Re: No validation with a bound NSTableView and custom NSFormatter
- From: Ben Kennedy <email@hidden>
- Date: Fri, 04 May 2012 11:17:02 -0700
> On May 3, 2012, at 6:11 PM, Ben Kennedy wrote:
>
>> Separate from the above, I also have a new performance problem. The loop in which I do my cascading updates executes inordinately slowly; simply assigning new values for two properties takes about 0.45 seconds when iterating a data set of a mere 135 objects. It used to be instantaneous before bindings came into the picture. I suspect that all of the KVO overhead is to blame (a quick peek in Instruments supports this).
In defence of KVO, I must rescind this hasty conclusion. The real problem occurred to me in the shower this morning: the array controller was constantly re-sorting the data after every property change, by virtue of its sortDescriptors. By temporarily clearing the sortDescriptors before the loop (and restoring afterwards), performance is golden again. I should have realized this earlier.
On 03 May 2012, at 8:04 pm, Keary Suska wrote:
> Don't get me wrong, I think bindings are great, and I use them extensively in almost everything I do. But it seems to me they are really built for straightforward usage and if you need to stretch them they tend to break. Not to mention that they are completely opaque and are a bear to debug.
Having not used bindings much (despite their availability for many years), I appreciate your experience and perspective, because it's in line with the impressions I've nonetheless been forming. (Cocoa bindings sort of remind me of BOOPSI from the Amiga days, akin to a well-intentioned but awkward and gangly teenager.)
The motivation for moving my delegate-based table to a bound data source was in part to simplify the code needed for sorting and filtering in the UI -- but I was a bit naïve about the additional work implied by some of the trade-offs.
thanks,
b
--
Ben Kennedy, chief magician
Zygoat Creative Technical Services
http://www.zygoat.ca
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