【设计模式】装饰者模式

※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 IPrice

10     {

11         decimal Cost { get; set; }

12     }

13 }

View Code

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 : IPrice

10     {

11         private decimal _cost;

12 

13         public decimal Cost

14         {

15             get

16             {

17                 return _cost;

18             }

19             set

20             {

21                 _cost = value;

22             }

23         }

24     }

25 }

View Code

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 : IPrice

10     {

11         private IPrice _basePrice;

12 

13         public TradeDiscountPriceDecorator(IPrice price)

14         {

15             _basePrice = price;

16         }

17 

18         public decimal Cost

19         {

20             get

21             {

22                 return _basePrice.Cost * 0.95m;

23             }

24             set

25             {

26                 _basePrice.Cost = value;

27             }

28         }

29     }

30 }

View Code

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 : IPrice

10     {

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 Cost

22         {

23             get

24             {

25                 return _basePrice.Cost * _exchangeRate;

26             }

27             set

28             {

29                 _basePrice.Cost = value;

30             }

31         }

32     }

33 }

View Code

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 Product

10     {

11         public IPrice Price { get; set; }

12     }

13 }

View Code

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 ProductService

10     {

11         private IProductRepository _productRepository;

12 

13         public ProductService(IProductRepository productRepository)

14         {

15             _productRepository = productRepository;

16         }

17 

18         public IEnumerable<Product> GetAllProduct()

19         {

20             IEnumerable<Product> products = _productRepository.FindAll();

21 

22             products.ApplyTradeDiscount();

23 

24             products.ApplyCurrencyMultiplier(0.78m);

25 

26             return products;

27         }

28     }

29 }

View Code

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 IProductRepository

10     {

11         IEnumerable<Product> FindAll();

12     }

13 }

View Code

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 ProductCollectionExtensionMethods

10     {

11         public static void ApplyCurrencyMultiplier(this IEnumerable<Product> 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<Product> products)

20         {

21             foreach (Product p in products)

22             {

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

24             }

25         }

26     }

27 }

View Code

---

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<Product> 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 }

View Code

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 : IProductRepository

11     {

12         public IEnumerable<Product> FindAll()

13         {

14             IEnumerable<Product> 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 }

View Code