public static List <string> SortInWillysOrder(List <string> ShoppingCart, List <StoreStructure> assortment) { List <string> assortmentWillys = StoreStructure.CreateWillysSortimentOrder(assortment); var willysList = new List <string>(); foreach (string m in assortmentWillys) { foreach (string s in ShoppingCart) { if (s == m) { willysList.Add(s); } } } return(willysList); }