※文件引自OneDrive，有些人可能看不到

代码如下：

IPrice

1 using System; 2 using System.Collections.Generic; 3 using System.Linq; 4 using System.Text; 5 using System.Threading.Tasks; 6  7 namespace Model 8 { 9     public interface IPrice10     {11         decimal Cost { get; set; }12     }13 }

BasePrice

1 using System; 2 using System.Collections.Generic; 3 using System.Linq; 4 using System.Text; 5 using System.Threading.Tasks; 6  7 namespace Model 8 { 9     public class BasePrice : IPrice10     {11         private decimal _cost;12 13         public decimal Cost14         {15             get16             {17                 return _cost;18             }19             set20             {21                 _cost = value;22             }23         }24     }25 }

TradeDiscountPriceDecorator

1 using System; 2 using System.Collections.Generic; 3 using System.Linq; 4 using System.Text; 5 using System.Threading.Tasks; 6  7 namespace Model 8 { 9     public class TradeDiscountPriceDecorator : IPrice10     {11         private IPrice _basePrice;12 13         public TradeDiscountPriceDecorator(IPrice price)14         {15             _basePrice = price;16         }17 18         public decimal Cost19         {20             get21             {22                 return _basePrice.Cost * 0.95m;23             }24             set25             {26                 _basePrice.Cost = value;27             }28         }29     }30 }

CurrencyPriceDecorator

1 using System; 2 using System.Collections.Generic; 3 using System.Linq; 4 using System.Text; 5 using System.Threading.Tasks; 6  7 namespace Model 8 { 9     public class CurrencyPriceDecorator : IPrice10     {11         private IPrice _basePrice;12 13         private decimal _exchangeRate;14 15         public CurrencyPriceDecorator(IPrice price, decimal exchangeRate)16         {17             _basePrice = price;18             _exchangeRate = exchangeRate;19         }20 21         public decimal Cost22         {23             get24             {25                 return _basePrice.Cost * _exchangeRate;26             }27             set28             {29                 _basePrice.Cost = value;30             }31         }32     }33 }

Product

1 using System; 2 using System.Collections.Generic; 3 using System.Linq; 4 using System.Text; 5 using System.Threading.Tasks; 6  7 namespace Model 8 { 9     public class Product10     {11         public IPrice Price { get; set; }12     }13 }

ProductService

1 using System; 2 using System.Collections.Generic; 3 using System.Linq; 4 using System.Text; 5 using System.Threading.Tasks; 6  7 namespace Model 8 { 9     public class ProductService10     {11         private IProductRepository _productRepository;12 13         public ProductService(IProductRepository productRepository)14         {15             _productRepository = productRepository;16         }17 18         public IEnumerable
      
        GetAllProduct()19         {20             IEnumerable
       
         products = _productRepository.FindAll();21 22             products.ApplyTradeDiscount();23 24             products.ApplyCurrencyMultiplier(0.78m);25 26             return products;27         }28     }29 }
       
      

IProductRepository

1 using System; 2 using System.Collections.Generic; 3 using System.Linq; 4 using System.Text; 5 using System.Threading.Tasks; 6  7 namespace Model 8 { 9     public interface IProductRepository10     {11         IEnumerable
      
        FindAll();12     }13 }
      

ProductCollectionExtensionMethods

1 using System; 2 using System.Collections.Generic; 3 using System.Linq; 4 using System.Text; 5 using System.Threading.Tasks; 6  7 namespace Model 8 { 9     public static class ProductCollectionExtensionMethods10     {11         public static void ApplyCurrencyMultiplier(this IEnumerable
      
        products, decimal exchangeRate)12         {13             foreach (Product p in products)14             {15                 p.Price = new CurrencyPriceDecorator(p.Price, exchangeRate);16             }17         }18 19         public static void ApplyTradeDiscount(this IEnumerable
       
         products)20         {21             foreach (Product p in products)22             {23                 p.Price = new TradeDiscountPriceDecorator(p.Price);24             }25         }26     }27 }
       
      

---

Program

1 using DecoratorConsole.Test; 2 using Model; 3 using System; 4 using System.Collections.Generic; 5  6 namespace DecoratorConsole 7 { 8     class Program 9     {10         static void Main(string[] args)11         {12             ProductService service = new ProductService(new TestPorductRepository());13             IEnumerable
      
        products = service.GetAllProduct();14 15             foreach (Product p in products)16             {17                 Console.WriteLine(string.Format("Product's Price : {0}", p.Price.Cost));18             }19 20             Console.ReadLine();21         }22     }23 }
      

TestPorductRepository

1 using Model; 2 using System; 3 using System.Collections.Generic; 4 using System.Linq; 5 using System.Text; 6 using System.Threading.Tasks; 7  8 namespace DecoratorConsole.Test 9 {10     public class TestPorductRepository : IProductRepository11     {12         public IEnumerable
      
        FindAll()13         {14             IEnumerable
       
         products = new Product[] {15                 new Product() { Price = new BasePrice() { Cost = 100m }},16                 new Product() { Price = new BasePrice() { Cost = 200m }},17                 new Product() { Price = new BasePrice() { Cost = 50m }},18                 new Product() { Price = new BasePrice() { Cost = 240.5m }},19                 new Product() { Price = new BasePrice() { Cost = 500m }},20                 new Product() { Price = new BasePrice() { Cost = 1000m }},21                 new Product() { Price = new BasePrice() { Cost = 1500m }},22             };23 24             return products;25         }26     }27 }