[Route("cars/list/{orderby?}")]  // URL:  https://localhost:5001/cars/list/color
        public IActionResult List(string orderby)
        {
            // Andy:  Check for null
            if (orderby == null)
            {
                orderby = "";
            }

            //MakeModel, Year, Price, Milage, Color
            CarContext.SortOrder sortOrder;
            sortOrder = CarContext.SortOrder.Year;


            orderby = orderby.ToLower();
            switch (orderby)
            {
            case "id":
                sortOrder = CarContext.SortOrder.ID;
                break;

            case "make":
                sortOrder = CarContext.SortOrder.MakeModel;
                break;

            case "mileage":
                sortOrder = CarContext.SortOrder.Mileage;
                break;

            case "price":
                sortOrder = CarContext.SortOrder.Price;
                break;

            case "color":
                sortOrder = CarContext.SortOrder.Color;
                break;

            case "year":
                sortOrder = CarContext.SortOrder.Year;
                break;
            }

            List <Car> sortedCars = CarContext.sortBy(sortOrder, true);

            return(View(sortedCars));
        }