On May 17, 2013, at 1:18 AM, Trygve Inda wrote: >> On May 17, 2013, at 12:43 AM, Trygve Inda wrote: >> >>> The trouble comes in the fact that I need to be able to add properties at >>> runtime. For the dictionary option, it is easy - just make sure the key >>> names don't collide and I can add more keys to each dictionary. >>> >>> But for the objects I don't see a nice way to do this >>> >>> There is setValue:forUndefinedKey: and then each object could keep a local >>> dictionary of these "defined at runtime" keys. >> >> That seems "nice" enough to me. The trick is that the custom class has to be >> sure to only modify the properties via KVC on itself, not the dictionary, in >> order to maintain KVO compliance. Another way to put it is that only >> -setValue:forUndefinedKey: should ever mutate the dictionary (and it should >> only be invoked by the KVC machinery itself). > > Will that work right if I have an NSTableView and one of the columns has a > binding to "myCustomProperty" (which is not defined in the object model)... > Will it get sent: > > [someObject setValue:someValue forUndefinedKey:myCustomProperty] > > Rather than: > > [someObject setMyCustomProperty:someValue];
Bindings use KVC. They will do: [someObject setValue:someValue forKey:@"myCustomProperty"]; The KVC machinery is what will eventually call [someObject setValue:someValue forUndefinedKey:@"myCustomProperty"] for the dynamic properties. (For the predefined properties, it will invoke your setter methods.) > On disk the data will be stored in a plist and an array of NSDictionaryies > (some of the key will be required and predefind) but some will be user > defined. > > When I load the data from disk if I use dictionary obejects, I don't have to > do anything else but if I use custom objects I would have to create them and > send > > [someObject setValue:someValue forUndefinedKey:myCustomProperty] > > To each object. > > Right? You can use -setValuesForKeysWithDictionary: to set all of the properties of your object from a dictionary. That uses KVC on each key-value pair, so it works like I described above for bindings. That said, you should consider doing proper keyed archiving of your class. Don't forget the limits of property lists. Regards, Ken _______________________________________________ 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
