private static IEnumerable<ItemCategory> GetItemCategorySubcategories(ItemCategory parentCategory, IEnumerable<ItemCategory> categories)
{
var subCategories = categories.Where(c => c.ParentItemCategoryID == parentCategory.ItemCategoryID).ToList();
foreach (var subCategory in subCategories)
{
subCategory.Subcategories = GetItemCategorySubcategories(subCategory, categories);
}
return subCategories;
}