Printing Flags Enum as Separate Flags

Using the extension methods I've written here on a related question, this should be simple:

var value = MyEnum.Default;
var str = String.Join(", ", value.GetIndividualFlags());
// "Choice1, Choice2"

And here's the extension methods:

static class EnumExtensions
{
    public static IEnumerable<Enum> GetFlags(this Enum value)
    {
        return GetFlags(value, Enum.GetValues(value.GetType()).Cast<Enum>().ToArray());
    }

    public static IEnumerable<Enum> GetIndividualFlags(this Enum value)
    {
        return GetFlags(value, GetFlagValues(value.GetType()).ToArray());
    }

    private static IEnumerable<Enum> GetFlags(Enum value, Enum[] values)
    {
        ulong bits = Convert.ToUInt64(value);
        List<Enum> results = new List<Enum>();
        for (int i = values.Length - 1; i >= 0; i--)
        {
            ulong mask = Convert.ToUInt64(values[i]);
            if (i == 0 && mask == 0L)
                break;
            if ((bits & mask) == mask)
            {
                results.Add(values[i]);
                bits -= mask;
            }
        }
        if (bits != 0L)
            return Enumerable.Empty<Enum>();
        if (Convert.ToUInt64(value) != 0L)
            return results.Reverse<Enum>();
        if (bits == Convert.ToUInt64(value) && values.Length > 0 && Convert.ToUInt64(values[0]) == 0L)
            return values.Take(1);
        return Enumerable.Empty<Enum>();
    }

    private static IEnumerable<Enum> GetFlagValues(Type enumType)
    {
        ulong flag = 0x1;
        foreach (var value in Enum.GetValues(enumType).Cast<Enum>())
        {
            ulong bits = Convert.ToUInt64(value);
            if (bits == 0L)
                //yield return value;
                continue; // skip the zero value
            while (flag < bits) flag <<= 1;
            if (flag == bits)
                yield return value;
        }
    }
}

Decorate your enum with FlagsAttribute. It does pretty much exactly what you're after:

[Flags]
public enum FooNum
{
    foo = 0,
    bar = 1,
    lulz = 2,
    borkbork = 4
}

FooNum f = FooNum.bar | FooNum.borkbork;

Debug.WriteLine(f.ToString());

should give you:

bar, borkbork