key-value-coding

When I bind a control to an NSArrayController using Interface Builder, there are a variety of options under the "Controller Key" field in the bindings inspector. I understand what "arrangedObjects" is, and I semi-understand what "selection" is, but I'd love to see a really nice explanation of all the options and when to use each one. The list includes: selectionIndexes, selectionIndex, selectedObject, sortDescriptors, etc. I haven't been able to find a good explanation of these options. I'm having trouble with a button that's bound to target > selection, so I'm hoping a much deeper

I'm getting the following output: *** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<NSManagedObject 0x21016610> setValue:forUndefinedKey:]: the entity MyEntity is not key value coding-compliant for the key "aBooleanKey".' The code that runs before I get the output is the following: self.name = [managedObject valueForKey:@"name"]; self.language = [managedObject valueForKey:@"language"]; self.ownerID = [managedObject valueForKey:@"ownerID"]; // the following line is the scope of the problem: self.aBooleanKey = [[managedObject valueForKey:@"aBooleanKey"] boolValue]

I'm trying to implement an indexed accessor method for my model class in Python, as per the KVC guide . I want to use the optional ranged method, to load multiple objects at once for performance reasons. The method takes a pointer to a C-array buffer which my method needs to copy the objects into. I've tried something like the following, which doesn't work. How do I accomplish this? @objc.accessor # i've also tried @objc.signature('v@:o^@') def getFoos_range_(self, range): return self._some_array[range.location:range.location + range.length] Edit : I finally found the type encodings reference

I can't find in the Docs where they explain all those fields and what they mean. Especially "Controller Key" is not clear to me. The Controller Key pop-up menu is a way to help you discover what keys the controller (typically a NSArrayController, NSObjectController or a NSTreeController) presents. The best example is the selection key of NSArrayControllers, which contains the set of selected objects. What is confusing is the NSObjectController presents a 'selection' key too, although the controller can control only a single object (therefore the selection = the object). I agree that it is not

I was reading : Collection Accessor Patterns for To-Many Properties , but I'm not sure where can I or should I use this. Can someone please point out some scenarios that I can use Collection Accessor Patterns for To-Many Properties to make my code better or make my code writing easier? The collection accessor patterns that you were reading about improve the way key value coding works with collections like NSArray, NSDictionary, etc. If you implement them in your own classes, your classes can be used with KVC just like the standard collection classes. For example, maybe you've got a Flight

Hey. I am reading in a string from a file and attempting to use the resulting string to set a BOOL property on an object using the KVC method -setValue:forKeyPath: . However, this breaks with an exception: -[NSCFString charValue]: unrecognized selector sent to instance 0x7fff711023b0 . I'm guessing this is because BOOL is typedef'd from char. Is there a way around this? Thanks! When setting a BOOL property using KVC, you need to pass an NSNumber object. What you could do in your case is pass [NSNumber numberWithBool:[myString boolValue]] . That should fix your crash. I am catching the

Is it possible to key-value code (KVC) with native Swift data structures such as Array and Dictionary? Key-Value coding is still available for NSFoundation structures within Swift, just like in Objective C. For example, this is valid: var nsarray: NSArray = NSArray() // Fill the array with objects var array: NSArray = nsarray.valueForKeyPath("key.path") But this is invalid: var swiftarray: Array = [] // Fill the array with objects var array = swiftarray.valueForKeyPath("key.path") // Invalid, produces a compile-time error It seems that KVC on native Swift objects is just not supported. Here's