Why don't I get InvalidCastException when casting enum to integer fails?

Question

public enum Animal
{
    Dog = 1,
    Cat = 2,
    Cow = 3
}

int animalID = 4;
if ((Animal)animalID == Animal.Dog) // does not throw exception

animalID can't be casted to Animal.
Why don't I get InvalidCastException when casting enum to integer fails?

Answer 1

Because it's not an invalid cast.

The value you are casting is out of range for the enum (in this case) but it's not invalid.

As the approved types for an enum are byte, sbyte, short, ushort, int, uint, long, or ulong a cast from integer to enum is perfectly legal.

Source - MSDN