when to use “willChangeValueForKey” and “didChangeValueForKey”?

Question

I saw these lines in a demo project, but I couldn\'t understand why it did that.

[self willChangeValueForKey:@\"names\"];
[self didChangeValueForKey:@\"names\"];         


        

Answer 1

• If you want to do stuff just before the value gets changed, use willChangeValueForKey.
• If you want to do stuff just after the value gets changed, use didChangeValueForKey.

Edit: ignore me, was reading too fast - Barry is right :-)