public List<Item> Randomize()
{
List<Item> L1, L2 = null;
L1 = Items.Where(g => g.ItemType.Equals(ItemTypeEnum.Pretest)).Take(2).ToList<Item>();
L2 = Items.Where(p => !L1.Any(p2 => p2.ItemId == p.ItemId)).ToList<Item>();
return L1.Concat(L2).ToList();
}