On 01 May 2012, at 9:09 pm, Quincey Morris wrote: > When you bind one or more table columns to an array controller, the table > view automatically binds its own content binding to the array controller > (presumably with some heuristic for choosing one out of several, if you > happened to bind different columns different ways). It doesn't seem > impossible that the table view honors cell formatter errors only when its > content binding isn't used (i.e. pure data source for all columns).
That seems like a reasonable explanation (although I see no inherent reason why it must be the case, nor have I found it documented, alas.) I have re-worked things to take full advantage of bindings now, so as to get the more desirable automated validation handling. However, I've now come up against another challenge. As I may have alluded in an earlier posting, I need to be able to perform a cascading update on the data set in response to a particular row being edited. Previously, this was trivial to do with a for loop in the delegate's -[tableView:setObjectValue:forTableColumn:row:], but now requires some trickery. I've found myself overriding -[editColumn:row:withEvent:select:] and -[textShouldEndEditing:] in a NSTableView subclass in order to have a hook into performing an operation post-edit in relation to the modified row. This feels filthy, but I yet haven't seen how better to do it. I considered that I could register as a KVO observer for each of my data objects (and then use [arrayController.arrangedObjects indexOfObject:object] as the basis for my cascading update), but that requires adding extra -[addObserver:...] code accompanying everywhere I have an [arrayController addObject:], which seems prone to oversight. Is there a better way? 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). Is there something fundamental I'm missing to avoid this bottleneck? thanks, b -- Ben Kennedy, chief magician Zygoat Creative Technical Services http://www.zygoat.ca _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
