Why can't we add static methods to enums? [duplicate]

Question

I wonder why we can't add static methods (only methods, not properties) into enums? Is there any explanation for that?

It would be very useful if it was allowed.

And I also want to learn who forbids us to do it? Is it IL or C#?

Edit:

I don't want to use extension methods. Because I dont need to pass an instance of that enum. I don't need it's value there...

I want to call something like FooTypes.GetGoodFoos() not something FooTypes.BadFoo.GetSomething()

Edit 2:

Is that only me who thinks this could be more useful rather than writing this method in another class?

public enum Colors
{
    Red,
    LightRed,
    Pink,
    /* .
       .
       . */
    Green

    public static Colors[] GetRedLikes()
    {
        return new Colors[]
        {
            Colors.Red,
            Colors.LightRed,
            Colors.Pink
        }
    }
}

Answer 1

As the other answers say, it's not possible.

I know, this does not answer your question, but I want to give an alternative to your example. Because, basically what you try to archive is already possible with flags. So let me take your "GetRedLikes" example:

[Flags]
public enum Colors : byte
{
    Transparent = 0,                                         // = 0 (00000000)
    Red         = 1 << 0,                                    // = 1 (00000001)
    LightRed    = 1 << 1,                                    // = 2 (00000010)
    Pink        = 1 << 2,                                    // = 4 (00000100)
    Green       = 1 << 3,                                    // = 8 (00001000)

    RedLikes    = Colors.Red | Colors.LightRed | Colors.Pink // = 7 (00000111)
}

Then Colors.RedLikes will contain Red, LightRed and Pink. All the magic is done by bits, as always. Your condition then should look like this:

Colors c = Colors.LightRed;
if(c & Colors.RedLikes != 0)
{
    // c is red-alike
}

Of course, this solution will not allow you to do very complex algorithms, it's no method type replacement. But it allows you to combine more than one enum in a set. If you need further functions, you have to build a method in an extra class.

Answer 2

I use static class for same cases:

 public enum SomeEnum
{
    Item1,
    Item2,
    Item3
}

public static class SomeEnumHelper
{
    public static SomeEnum[] GetMainItems() 
    {
        return new[] {SomeEnum.Item1, SomeEnum.Item2};
    }
}