MVC扩展控制器工厂,通过继承DefaultControllerFactory来决定使用哪个接口实现,使用Ninject

希望实现的效果是：对购物车中所有商品的总价，实现9折或8折：

当点击"9折"：

当点击"8折"：

□ 思路

8折或9折是打折接口的不同实现，关键是：由什么条件决定使用哪种打折方式？

--当点击8折或9折链接的时候，把参数放在路由中，然后在自定义控制器工厂中根据参数的不同选择使用哪种打折方式。

□ model

public class CartLine
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public decimal Price { get; set; }
        public int Quantity { get; set; }
    }

□ 接口

using MvcApplication2.Models;

namespace MvcApplication2
{
    public interface IDiscount
    {
        decimal GetFinalPrice(List<CartLine> cartLines);
    }
}

□ 接口的2种实现

using System.Collections.Generic;

namespace MvcApplication2.implementation

{

    public class NineDiscount : IDiscount

    {

        public decimal GetFinalPrice(List<Models.CartLine> cartLines)

        {

            decimal result = 0.0M;

            foreach (var item in cartLines)

            {

                result += item.Price*item.Quantity;

            }

            return result*(90M/100M);

        }

    }

}

using System.Collections.Generic;

namespace MvcApplication2.implementation

{

    public class EightDiscount : IDiscount

    {

        public decimal GetFinalPrice(List<Models.CartLine> cartLines)

        {

            decimal result = 0.0M;

            foreach (var item in cartLines)

            {

                result += item.Price * item.Quantity;

            }

            return result * (80M / 100M);

        }

    }

}

□ HomeController

using System.Collections.Generic;

using System.Web.Mvc;

using MvcApplication2.Models;

namespace MvcApplication2.Controllers

{

    public class HomeController : Controller

    {

        public ActionResult Index()

        {

            List<CartLine> cartLines = new List<CartLine>()

            {

                new CartLine(){Id = 1, Name = "Product1", Price = 80M, Quantity = 2},

                new CartLine(){Id = 2, Name = "Product2", Price = 100M, Quantity = 3},

            };

            Session["cart"] = cartLines;

            return View(cartLines);

        }

    }

}

□ Home/Index.cshtml

把不同的打折方式放在路由中传递。

@model List<MvcApplication2.Models.CartLine>

@{

    ViewBag.Title = "Index";

    Layout = "~/Views/Shared/_Layout.cshtml";

}

<h2>Index</h2>

<table>

    <tr style="background-color: #e3e3e3;">

        <td>产品</td>

        <td>价格</td>

        <td>数量</td>

    </tr>

    @foreach (var item in Model)

    {

        <tr>

            <td>@item.Name</td>

            <td>@string.Format("{0:C}", item.Price)</td>

            <td>@item.Quantity</td>

        </tr>

    }

</table>

<p>

    @Html.ActionLink("9折购买", "Index", "Shop", new {policy = "Nine"},new {})

</p>

<p>

    @Html.ActionLink("8折购买", "Index", "Shop", new {policy = "Eight"},new {})

</p>    

□ 自定义控制器工厂，使用Ninject，根据路由参数policy的不同，决定选择具体的打折接口实现

using System;

using System.Web.Mvc;

using System.Web.Routing;

using MvcApplication2.implementation;

using Ninject;

namespace MvcApplication2.Extension

{

    public class NinjectControllerFactory : DefaultControllerFactory

    {

        IKernel ninjectKernel;

        string policy = "";

        public NinjectControllerFactory()

        {

            ninjectKernel = new StandardKernel();

        }

        protected override IController GetControllerInstance(RequestContext requestContext, Type controllerType)

        {

            if (requestContext.RouteData.Values["policy"] != null)

            {

                policy = requestContext.RouteData.Values["policy"].ToString();

            }

            AddBindings();

            return controllerType == null ? null : (IController) ninjectKernel.Get(controllerType);

        }

        private void AddBindings()

        {

            switch (policy)

            {

                case "Eight":

                    ninjectKernel.Rebind<IDiscount>().To<EightDiscount>();

                    break;

                case "Nine":

                    ninjectKernel.Rebind<IDiscount>().To<NineDiscount>();

                    break;

                default:

                    ninjectKernel.Rebind<IDiscount>().To<NineDiscount>();

                    break;

            }

        }

    }

}

□ 自定义控制器工厂全局注册

ControllerBuilder.Current.SetControllerFactory(new NinjectControllerFactory());

□ ShopController中使用打折接口方法

using System;

using System.Collections.Generic;

using System.Web.Mvc;

using MvcApplication2.Models;

namespace MvcApplication2.Controllers

{

    public class ShopController : Controller

    {

        public IDiscount _Discount;

        public ShopController(IDiscount discount)

        {

            this._Discount = discount;

        }

        public ActionResult Index(string policy)

        {

            List<CartLine> cartLines = new List<CartLine>();

            if (Session["cart"] != null)

            {

                cartLines = (List<CartLine>)Session["cart"];

            }

            ViewData["total"] = String.Format("{0:C}",_Discount.GetFinalPrice(cartLines));

            return View();

        }

    }

}

□ Shop/Index.cshtml

@{

    ViewBag.Title = "Index";

    Layout = "~/Views/Shared/_Layout.cshtml";

}

打折后的价格为： @ViewData["total"]

□ 自定义路由

为了让url更直观，符合controller/action/paramter：

            routes.MapRoute(

                name: "Default",

                url: "{controller}/{action}/{policy}",

                defaults: new { controller = "Home", action = "Index", policy = UrlParameter.Optional }

            );