How to limit a generic type parameter to System.Enum [duplicate]

Answer 1

There is no need to make your method generic in this way.

You can just use the System.Enum as the type parameter in your return type:

using System.Linq;
.
.
.
public IEnumerable GetValues(Enum value)
{
    return Enum.GetValues(value.GetType()).OfType();
}