Tree Structured Enumerations

using System;
using System.Collections.Generic;

namespace TreeStructuredEnumerations
{
    public class EnumUtility
    {
        public static bool IsChild<TType>(TType child, TType parent)
        {
            Type enumType = typeof(TType);
            Object[] attributeList = enumType.GetCustomAttributes(typeof(StructuredAttribute), true);

            if (attributeList.Length > 0)
            {
                StructuredAttribute attribute = (StructuredAttribute)attributeList[0];
                int span = attribute.Span;
                int parentIndex = (int)Convert.ChangeType(parent, typeof(int));
                int childIndex = (int)Convert.ChangeType(child, typeof(int));
                int index = childIndex / span;
                return (index == parentIndex && childIndex != parentIndex);
            }

            return true;
        }

        public static List<TType> CreateList<TType>(TType parent)
        {
            List<TType> result = new List<TType>();
            Type enumType = typeof (TType);
            TType[] enumValues = (TType[]) Enum.GetValues(enumType);

            foreach (TType enumValue in enumValues)
            {
                if (IsChild(enumValue, parent))
                {
                    result.Add(enumValue);
                }
            }

            return result;
        }
    }
}