static menthods in interfaces

Question

I want to create an interface with static methods so i can override these in a class. I know statics are class-level, but it doesnt seem right that an interface shouldnt allow a child class to override static methods. is there a work around or a keyword im missing? The reason is that im trying to mock an interface using NMock and it only supports interfaces as mockable types. As im working with some elses code, there are very few interfaces and most classes are static upto their eyeballs

Sean G · Answer

exactly what i thought with the singleton theory Alan... unfortunately ive been left with the Unit testing job and its seeming v.impossible as the coding architecture isnt too great. Almost every class within the business layer has static methods and it may take a while to convert them all to singletons then adding an Interface for each... then there is the issue of checking all the calls work within the whole application (250+ classes/code behinds) properly! thanks for the work around advice... i think its something to bare in mind within future projects...

Alan · Answer

One other thought I've just had is that if the classes consist of nothing else but static methods or you'll only ever create one instance then you could convert them to singletons. There's then no problem in the singletons implementing an interface and providing their own implementation of its methods/properties.

Alan · Answer

Well interfaces in C# don't support any kinds of static member and so there's nothing you can do about that. However as an alternative to implementing an interface you can inherit from an abstract class as long as the classes which you want to implement the static methods don't already inherit from another class (except of course System.Object). Notice though that even in abstract classes static methods and properties are never virtual though they can hide the base class implementation (or lack of one) with their own.