Helper method to get enum list with custom ordering

I have a client generated enum class with values already defined. I have to populate a dropdown list with all the enum values with a different order than the order they are declared in.

First, I thought its as simple as just rearranging the order they are declared in to the order I need and the method Enum.GetValues would return them in the new order. However, it still returns them in order of the enum value.

    public enum SampleEnum
    {
        Item1 = 0,
        Item2 = 1,
        Item3 = 2,
        Item4 = 3
    }

 var enumValues = Enum.GetValues(typeof(SampleEnum)).Cast<SampleEnum>();

 foreach (var item in enumValues)
 {
     Console.WriteLine(item.ToString());
 }

 Console.ReadLine();

Then I rearrange the order like this but the result is the same.

    public enum SampleEnum
    {
        Item2 = 1,
        Item3 = 2,
        Item1 = 0,
        Item4 = 3
    }

To solve this, I add a custom attribute called EnumOrder and then create a helper method that will return the enum values in this custom order.

    [AttributeUsage(AttributeTargets.Field)]
    public class EnumOrderAttribute : Attribute
    {
        public readonly int Order;

        public EnumOrderAttribute(int order)
        {
            Order = order;
        }
    }

    public static class Enums
    {
        public static IEnumerable<T> ToList<T>() where T : IConvertible
        {
            var type = typeof(T);
            if (!type.IsEnum)
                throw new System.ArgumentException($"{type.Name} is not an Enum.");

            var values = Enum.GetValues(type).Cast<T>().ToList();

            return values.OrderBy(x => {
                var memInfo = type.GetMember(type.GetEnumName(x));
                var orderAttributes = memInfo[0].GetCustomAttributes(typeof(EnumOrderAttribute), false);
                var order = orderAttributes.Length > 0
                    ? ((EnumOrderAttribute)orderAttributes.First()).Order
                    : Convert.ToInt32(x) + values.Count;

                return order;
            });

        }
    }

Then I use the attribute on my enum as below

    public enum SampleEnum
    {
        [EnumOrder(0)]
        Item2 = 1,

        [EnumOrder(1)]
        Item3 = 2,

        Item1 = 0,

        Item4 = 3
    }