public void AddProductionToInventory() { foreach (var pressMasterItem in Produced) { double units = pressMasterItem.UnitsMade; ProductMasterItem item = pressMasterItem.MasterItem; InventoryItem inventoryItem = StaticInventoryTracker.AllInventoryItems.FirstOrDefault(x => x.MasterID == item.MasterID && x.Grade == "WiP"); if (inventoryItem != null) { inventoryItem.AddUnits(units); } else { StaticInventoryTracker.AddInventory(item.ProductionCode, item.PiecesPerUnit, units, "WiP", item.MasterID); } } }