I need to do things differently in the shared delegate based on the controller type, so this probably won’t work. But thanks, I believe it will come in handy when I do need to branch on controllers themselves.
I do have a question though, since the method is a callback, and its signature is changed (with "Thing &” added), will NSFetchedResultsController be able to find it and call it? > On 8 Oct 2017, at 12:14 AM, C. Keith Ray <keith...@mac.com> wrote: > > Or make a base class for both Controller classes which defines todo () and > override todo() in each Controller class. > > -- > C. Keith Ray > > * https://leanpub.com/wepntk <https://leanpub.com/wepntk> <- buy my book? > * http://www.thirdfoundationsw.com/keith_ray_resume_2014_long.pdf > <http://www.thirdfoundationsw.com/keith_ray_resume_2014_long.pdf> > * http://agilesolutionspace.blogspot.com/ > <http://agilesolutionspace.blogspot.com/> > > On Oct 7, 2017, at 9:12 AM, C. Keith Ray <keith...@mac.com > <mailto:keith...@mac.com>> wrote: > >> You should be able to do this to avoid casting.(I think) >> >> protocol Thing { >> func todo() >> } >> >> class Controller1: NSFetchedResultsController<NSManagedObject>, Thing { >> func todo () {doOneThing} >> } >> class Controller2: NSFetchedResultsController<NSManagedObject>, Thing { >> func todo () {doAnotherThing} >> } >> >> func controllerWillChangeContent(_ controller: Thing & >> NSFetchedResultsController<NSFetchRequestResult>) { >> controller.todo() >> ... >> } >> >> -- >> C. Keith Ray >> >> * https://leanpub.com/wepntk <https://leanpub.com/wepntk> <- buy my book? >> * http://www.thirdfoundationsw.com/keith_ray_resume_2014_long.pdf >> <http://www.thirdfoundationsw.com/keith_ray_resume_2014_long.pdf> >> * http://agilesolutionspace.blogspot.com/ >> <http://agilesolutionspace.blogspot.com/> >> >> On Oct 6, 2017, at 11:28 PM, Glen Huang via swift-users >> <swift-users@swift.org <mailto:swift-users@swift.org>> wrote: >> >>> Hi, >>> >>> I defined some concrete classes inheriting from a generic class like this: >>> >>> class Controller1: NSFetchedResultsController<NSManagedObject> {} >>> class Controller2: NSFetchedResultsController<NSManagedObject> {} >>> >>> And I assign them a shared delegate, and in the delegate method: >>> >>> func controllerWillChangeContent(_ controller: >>> NSFetchedResultsController<NSFetchRequestResult>) >>> >>> I want to test the concrete type of controller, doing things differently >>> for Controller1 and Controller2. >>> >>> But doing the following gives me a warning: Cast from >>> 'NSFetchedResultsController<NSFetchRequestResult>' to unrelated type >>> 'Controller1’ always fails >>> >>> switch controller { >>> case is Controller1: >>> // ... >>> default: >>> break >>> } >>> >>> I wonder what’s the correct way to check the concrete type? >>> >>> Regards, >>> Glen >>> _______________________________________________ >>> swift-users mailing list >>> swift-users@swift.org <mailto:swift-users@swift.org> >>> https://lists.swift.org/mailman/listinfo/swift-users >>> <https://lists.swift.org/mailman/listinfo/swift-users>
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