Is `moc` declared in a non-"@objc" scope? I think there's a "@IBsomethingerather" that you have to put in front of those to let Interface Builder see them or something. Sorry I can't be more definitive, but I'm not in front of my computer and can't double-check.
HTH - Dave Sweeris Sent from my iPhone > On Jan 16, 2017, at 10:11, Jean-Denis Muys via swift-users > <swift-users@swift.org> wrote: > > Hi, > > I am exploring the use of Swift for a Mac Cocoa application - using Xcode > 8.2.1, and it seems I hit a roadblock regarding Cocoa bindings. > > In this toy Core Data document-based project, I added an NSArrayController in > the StoryBoard. I need to bind it a NSManagedObjectContext so that my user > interface works by itself. I followed the solution outlined in Technical Q&A > QA1871 (https://developer.apple.com/library/content/qa/qa1871/_index.html). > > So I want to add a property of type ManagedObjectContext to my ViewController > class. > > I naturally declared it as an optional: > > var moc: ManagedObjectContext? > > But when I enter the property name in the bindings inspector of > InterfaceBuilder, it complains: there is a red exclamation mark, and hovering > over it pops up this error message: > > “The Managed Object Context binding expects to be bound to an object of type > NSObject, but mac is of type ManagedObjectContext?” > > And it fails at run time too. > > changing the type to ManagedObjectContext! doesn’t help: IB complains in > exactly the same way. > > changing the type to a non optional ManagedObjectContext silences the IB > error, but now my ViewController class doesn’t compile anymore. The error I > get is: > > class ViewController has no initialiser > > I completely understand this error message. And I can add an initialiser. But > I get this new error message: > > property ‘self.moc’ not initialised at super.init call. > > I understand that one too, but what can I do? At initialiser-time, the > managedObjectContext is not yet known. In Objective-C I would set it to nil, > which I cannot do since the property is not an optional any more. > > Do I really need to allocate a dummy sentinel ManagedObjectContext, just to > make the compiler happy? > > This would be ugly as hell, far worse than the nil value we use in > Objective-C. Swift in that case, would not be safer, but less safe than Obj-C. > > I find this idea repulsive. Or did I miss something? > > Or is Swift fundamentally incompatible with Cocoa bindings? That would be a > pity too. > > Thanks, > > Jean-Denis > > > _______________________________________________ > swift-users mailing list > swift-users@swift.org > https://lists.swift.org/mailman/listinfo/swift-users _______________________________________________ swift-users mailing list swift-users@swift.org https://lists.swift.org/mailman/listinfo/swift-users
