Neatest way to 'OR' all values in a Flagged Enum?

Question

Given the enum:

[Flags]
public enum mytest
{
    a = 1,
    b = 2,
    c = 4
}

I\'ve come up with two ways to represent all va

Answer 1

It is not as easy as it looks at first sight given the underlying type cast issues:

static public TEnum GetAllFlags() where TEnum : struct, IComparable, IFormattable, IConvertible
    {
        unchecked
        {
            if (!typeof(TEnum).IsEnum)
                throw new InvalidOperationException("Can't get flags from non Enum");
            object val = null;
            switch (Type.GetTypeCode(Enum.GetUnderlyingType(typeof(TEnum))))
            {
                case TypeCode.Byte:
                case TypeCode.SByte:
                    val = Enum.GetValues(typeof(TEnum))
                                .Cast()
                                .Aggregate(default(Byte), ( s, f) => (byte)(s | f));
                    break;
                case TypeCode.Int16:
                case TypeCode.UInt16:
                    val = Enum.GetValues(typeof(TEnum))
                                .Cast()
                                .Aggregate(default(UInt16), ( s, f) => (UInt16)(s | f));
                    break;
                case TypeCode.Int32:
                case TypeCode.UInt32:
                    val = Enum.GetValues(typeof(TEnum))
                                .Cast()
                                .Aggregate(default(UInt32), ( s, f) => (UInt32)(s | f));
                    break;
                case TypeCode.Int64:
                case TypeCode.UInt64:
                    val = Enum.GetValues(typeof(TEnum))
                                .Cast()
                                .Aggregate(default(UInt64), ( s, f) => (UInt64)(s | f));
                    break;
                default :
                    throw new InvalidOperationException("unhandled enum underlying type");

            }
            return (TEnum)Enum.ToObject(typeof(TEnum), val);
        }
    }

More about this kind of conversions can be found here