How to convert from System.Enum to base integer?

Solution 1:

If you don't want to cast,

Convert.ToInt32()

could do the trick.

The direct cast (via (int)enumValue) is not possible. Note that this would also be "dangerous" since an enum can have different underlying types (int, long, byte...).

More formally: System.Enum has no direct inheritance relationship with Int32 (though both are ValueTypes), so the explicit cast cannot be correct within the type system

Solution 2:

I got it to work by casting to an object and then to an int:

public static class EnumExtensions
{
    public static int ToInt(this Enum enumValue)
    {
        return (int)((object)enumValue);
    }
}

This is ugly and probably not the best way. I'll keep messing with it, to see if I can come up with something better....

EDIT: Was just about to post that Convert.ToInt32(enumValue) works as well, and noticed that MartinStettner beat me to it.

public static class EnumExtensions
{
    public static int ToInt(this Enum enumValue)
    {
        return Convert.ToInt32(enumValue);
    }
}

Test:

int x = DayOfWeek.Friday.ToInt();
Console.WriteLine(x); // results in 5 which is int value of Friday

EDIT 2: In the comments, someone said that this only works in C# 3.0. I just tested this in VS2005 like this and it worked:

public static class Helpers
{
    public static int ToInt(Enum enumValue)
    {
        return Convert.ToInt32(enumValue);
    }
}

    static void Main(string[] args)
    {
        Console.WriteLine(Helpers.ToInt(DayOfWeek.Friday));
    }