> On May 17, 2013, at 12:43 AM, Trygve Inda wrote: > >> I need to keep a small (few thousand) record database of sorts. Each record >> has some pre-detertermined fields, but the user can add there own fields to >> to a limited extent. … >> >> This will be simple objects in an NSMutableArray. >> >> I can use an array of NSMutableDictionaries or perhaps an array of >> class-based custom cocoa objects. > > Although dictionaries make for a nice quick and dirty object model, I find > that they very quickly become more cumbersome than they're worth. With the > amount of help that the compiler is providing these days, it's ridiculously > easy to make a small class that does little more than hold some properties. > > >> One nice thing about the object route is that I can have some fields >> (properties) be based on a calculation rather than real storage like they'd >> be in an NSMutableDictionary. > > Yup, that's the sort of case where the limits of dictionaries show up. > > >> 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]; 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? Thoughts on this? _______________________________________________ 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
