in AdventureWorksMVC/Business/ProductManager.cs [83:91]
public static List<string> GetProductColor(int categoryId)
{
List<string> colorList = null;
colorList = (from p in Common.DataEntities.Product
where p.Color != null && p.ProductSubcategory.ProductSubcategoryID == categoryId
orderby p.Color
select p.Color).Distinct().ToList();
return colorList;
}