Best exception for an invalid generic type argument

Question

I\'m currently writing some code for UnconstrainedMelody which has generic methods to do with enums.

Now, I have a static class with a bunch of methods which are

Answer 1

I'd go with NotSupportedException. While ArgumentException looks fine, it's really expected when an argument passed to a method is unacceptable. A type argument is a defining characteristic for the actual method you want to call, not a real "argument." InvalidOperationException should be thrown when the operation you're performing can be valid in some cases but for the particular situation, it's unacceptable.

NotSupportedException is thrown when an operation is inherently unsupported. For instance, when implementing an interface where a particular member doesn't make sense for a class. This looks like a similar situation.