I am working on some legacy code and have come across something that I’m not sure of. We have a class y that is declared inside of another class x. Class y is only ever used inside of class x but my question is why wouldn’t you create a separate class file and put class y in there instead of declaring it inside of class x? Isn’t this violating OOP’s or is it just a matter of style since it is only ever used inside of this class. I’m refactoring some of this code and my first reaction would be to separate class y out into it’s own file.
namespace Library { public class x { // methods, properties, local members of class x class y { // methods, properties, local members of class y } } }
You create an inner class because it is only ever used within the scope of class x and it logically fits in the factoring/architecture of class x.
Class y might also be privy to implementation details of class x that are not meant to be known to the public.