Have you ever seen design with reasonable usage of protected internal access modifier?

Question

I haven\'t, but I don\'t say there isn\'t one.

All of the C# developers who read this probably do know what is protected internal and when to use it. My question is simp

Answer 1

I'm sure you can think of examples, but in five years of C# development, I've not seen a good case for it. John K's example illustrates the intended use of the modifier nicely, however I think the requirements that lead to this situation are problematic. In John K's example, the class has "friendly" access within the assembly, and in general this is trouble, because those classes are probably "asking", not "telling" (programming is not polite, it is better to tell than to ask). In what case do you have a useful extendable class that Friends can call a method on but others cannot?

Another use would be for testing access (IE you want it to be protected, but internal so your assembly level tests can call it). This is a trouble situation too - when you expose things as internal for testing I think it is a design smell that dependency injection can usually handle.