How to get next (or previous) enum value in C#

Question

I have an enum which is defined like this:

public enum eRat { A = 0, B=3, C=5, D=8 };

So given value eRat.B, I want to get the

Answer 1

Seems like an abuse of the enum class to me - but this would do it (assuming that calling Next on the last value would cause wrap-around):

public static eRat Next(this eRat target)
{
    var nextValueQuery = Enum.GetValues(typeof(eRat)).Cast().SkipWhile(e => e != target).Skip(1);
    if (nextValueQuery.Count() != 0)
    {
        return (eRat)nextValueQuery.First();
    }
    else
    {
        return eRat.A;
    }
}

And this would give you the previous value on the same basis:

public static eRat Previous(this eRat target)
{
    var nextValueQuery = Enum.GetValues(typeof(eRat)).Cast().Reverse().SkipWhile(e => e != target).Skip(1);
    if (nextValueQuery.Count() != 0)
    {
        return (eRat)nextValueQuery.First();
    }
    else
    {
        return eRat.D;
    }
}