“Class of where T : Enum” not working [duplicate]

Answer 1

No I don't believe so. Yes use a design pattern to get around it, have the base class return the type that's allowed, and the derived classes can check for it.

HTH.

Answer 2

You can't do it because the spec says you can't, basically. It's annoying, but that's the way it is. The CLR supports it with no problem. My guess is that when generics were first being designed, the CLR might not have supported it, so it was prohibited in the language too... and either the C# team didn't get the memo about it then being supported, or it was too late too include it. Delegates are similarly annoying.

As for a workaround... have a look at my Unconstrained Melody project. You could use the same approach yourself. I wrote a blog post at the same time, which goes into more details.

Answer 3

it's not possible. But if you are interested in a runtime check you can do

class A<T>
        {
            static A()
            {
                if(!typeof(T).IsEnum)
                {
                    throw new Exception();
                }
            }
        }