C#原始类型扩展方法—this参数修饰符

   public static  class ProductCollectionExctensionMethods

    {

       public static void ApplyCurrencyMultiplier( this List<Product> products)

       {

           foreach (Product p in products)

           {

               p.Price = new CurrencyPriceDecorator(p.Price, 0.78m);

           }

       }

       public static void ApplyTradeDiscount( this List<Product> products)

       {

           foreach (Product p in products)

           {

               p.Price = new TradeDiscountPriceDecorator(p.Price);

           }

       }

    }

 调用

List<Product> products = new List<Product>(); products.ApplyCurrencyMultiplier(); products.ApplyTradeDiscount();