1.定义接口
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
namespace EssentialTools.Models
{
public interface IValueCalculator
{
decimal ValueProducts(IEnumerable<Product> products);
}
}
2.继承接口
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
namespace EssentialTools.Models
{
public class LinqValueCalculator : IValueCalculator
{
public decimal ValueProducts(IEnumerable<Product> products)
{
return products.Sum(p => p.Price);
}
}
}
3.购物车,商品对象，计算商品总价方法
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
namespace EssentialTools.Models
{
public class ShoppingCart
{
private IValueCalculator calc;
public ShoppingCart(IValueCalculator calcParam)
{
calc = calcParam; // 引入其他类帮助
}
public IEnumerable<Product> Products { get; set; }
public decimal CalculateProductTotal()
{
return calc.ValueProducts(Products);
}
}
}
4.控制器整合处理
private Product[] products = {
new Product {Name = "Kayak", Category = "Watersports", Price = 275M},
new Product {Name = "Lifejacket", Category = "Watersports", Price = 48.95M},
new Product {Name = "Soccer ball", Category = "Soccer", Price = 19.50M},
new Product {Name = "Corner flag", Category = "Soccer", Price = 34.95M}
};
public ActionResult Index()
{
IValueCalculator calc = new LinqValueCalculator();
ShoppingCart cart = new ShoppingCart(calc) { Products = products }; // 购物车中的商品
decimal totalValue = cart.CalculateProductTotal();
return View(totalValue);
}
5.页面展示
@model decimal
@{
Layout = null;
}
<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width" />
<title>Value</title>
</head>
<body>
<div>
Total value is $@Model
</div>
</body>
</html>