// Strategy contract

        public interface IBoatTraderInventoryLineItemPropertyBuildingStrategy

        {

            string BuildProperty(IEnumerable<ProductInstanceVersionLineItem> lineItems);

        }

// Strategy implementation for color property

        public sealed class BoatTraderInventoryLineItemColorPropertyBuildingStrategy : IBoatTraderInventoryLineItemPropertyBuildingStrategy

        {

            private static readonly List<int> ColorCategoryIds = new List<int>

            {

                1,2, 3, 4, 5, 6, 7,8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19,32,53,54,66,67

            };

            public string BuildProperty(IEnumerable<ProductInstanceVersionLineItem> lineItems)

            {

                var colorLineItems = lineItems.Where(x => ColorCategoryIds.Contains(x.ManufacturerInvoiceLineItemCategoryId));

                if (colorLineItems == null || colorLineItems.Count() == 0)

                {

                    return string.Empty;

                }

                var colors = new List<string>();

                foreach (var colorLineItem in colorLineItems)

                {

                    colors.Add(HttpUtility.HtmlEncode(

                            colorLineItem.ManufacturerInvoiceLineItemCategory.Name + ":" + colorLineItem.Description));

                }

                return string.Join(", ", colors);

            }

        }

// The property builder (or context in the pattern "language")

        public sealed class BoatTraderInventoryLineItemPropertyBuilder

        {

            public string GetPropertyValue(string propertyName, IEnumerable<ProductInstanceVersionLineItem> lineItems) =>

                propertyName switch

                {

                    // Add more strategies here

                    nameof(BoatTrader.inventoryItem.color_options) => new BoatTraderInventoryLineItemColorPropertyBuildingStrategy().BuildProperty(lineItems),

                    _ => throw new NotImplementedException(),

                };

        }

// Use it like this (builder would be injected, not new-ed up)

color_options = new BoatTraderInventoryLineItemPropertyBuilder().GetPropertyValue(nameof(BoatTrader.inventoryItem.color_options), lineItems),