枚举的 C# BaseType

Question

I have a enum Color , it may derive from long or byte or int , and I want to know what type does it really derive from, long or byte or int ? In the process, I have met 2 problems.

First, the Color is defined like below:

enum Color : long
{
    red = 1,
    black = 2,
    blue = 3
}

Problem 1

I write the code below to do such things:

Console.WriteLine(typeof(Color));    // ConsoleApp7.Color
Console.WriteLine(typeof(Color).BaseType);    // System.Enum

At this moment, I met my first problem: it's curious that typeof(Color).BaseType is System.Enum , because Color is a enum type.

So I'm wondering that whether you defining a enum type like enum Enum1 { ... } , it actually means that: class Enum1 : enum { ... } ?

Problem 2

Based on problem 1, if I want to get its real base type, I need to write:

Console.WriteLine(typeof(Color).BaseType.BaseType);

Its output is System.ValueType , we know that int , byte and long all are System.ValueType , how can I get the keyword long ?

Thanks.

Answer 1

You want an Underlying type, not Base type:

var underlyingType = Enum.GetUnderlyingType(typeof(ConsoleColor))

Also note that any specific enum (like your Color ) is a value type and base type of System.Enum is System.ValueType (despite the fact that System.Enum is a reference type). That's why your typeof(Color).BaseType.BaseType equals System.ValueType