MVC缓存,使用数据层缓存,添加或修改时让缓存失效

在"MVC缓存01,运用控制器缓存或数据层缓存"中，在数据层中可以设置缓存的有用时刻。但这个还不够"智能"，常常期望在修改或创立的时分使缓存失效，加载新的数据。

?

□ 思路

1、缓存是以键值<string, object="">寄存的，在创立缓存的时分，先把IDictionary<int,t>作为缓存内容存储,int为T的主键。

 

2、EF上下文保留的时分时分把改变保留到数据库，并更新缓存中的内容。

● 先找出上下文中状况为added或modified的实体：var changeobjects
● 把改变保留数据到数据库：context.SaveChanges()
● 依据缓存key获取类型为IDictionary<int,t>的缓存内容：var cacheData = Cache.Get("vehicles") as Dictionary<int, vehicle="">;
● 最终遍历这些改变的实体，更新缓存项：cacheData[vehicle.Id] = vehicle;

 

□ 缓存接口

    public interface ICacheProvider
    {
        object Get(string key);
        void Set(string key, object data, int cacheTime);
        bool IsSet(string key);
        void Invalidate(string key);
    }

 

□ 缓存接口完成

环绕using System.Runtime.Caching的MemoryCache.Default回来类型为ObjectCache的缓存特点完成缓存接口：获取缓存项、设置缓存、判别是不是设置缓存、清空缓存。

using System;
using System.Runtime.Caching;

namespace MvcApplication1.Cache
{
    public class DefaultCacheProvider : ICacheProvider
    {
        private ObjectCache Cache
        {
            get { return MemoryCache.Default; }
        }
        public object Get(string key)
        {
            return Cache[key];
        }

        public void Set(string key, object data, int cacheTime)
        {
            CacheItemPolicy policy = new CacheItemPolicy();
            policy.AbsoluteExpiration = DateTime.Now + TimeSpan.FromMinutes(cacheTime);
            Cache.Add(new CacheItem(key, data), policy);
        }

        public bool IsSet(string key)
        {
            return (Cache[key] != null);
        }

        public void Invalidate(string key)
        {
            Cache.Remove(key);
        }
    }
}

 

□ Model

    public partial class Vehicle
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public decimal Price { get; set; }
    }

 

□ 对于Vehicle的Repositoy接口：

using System.Collections.Generic;
using MvcApplication1.Models;

namespace MvcApplication1.Repository
{
    public interface IVehicleRepository
    {
        void ClearCache();
        IEnumerableGetVehicles();
        void Insert(Vehicle vehicle);
        void Update(Vehicle vehicle);
        void SaveChanges();
    }
}

□ 对于Vehicle的Repositoy接口完成：  

using System.Collections.Generic;
using System.Data;
using System.Data.Entity.Infrastructure;
using System.Linq;
using MvcApplication1.Cache;
using MvcApplication1.Models;
namespace MvcApplication1.Repository
{
    public class VehicleRepository : IVehicleRepository
    {
        protected DemoEntities DataContext { get; private set; }
        public ICacheProvider Cache { get; set; }

        public VehicleRepository() : this(new DefaultCacheProvider())
        {

        }

        public VehicleRepository(ICacheProvider cacheProvider)
        {
            this.DataContext = new DemoEntities();
            this.Cache = cacheProvider;
        }

        public void ClearCache()
        {
            Cache.Invalidate("vehicles");
        }

        public System.Collections.Generic.IEnumerable GetVehicles()
        {
            var vehicles = Cache.Get("vehicles") as IDictionary<int, Vehicle>;
            if (vehicles == null)
            {
                vehicles = DataContext.Vehicle.ToDictionary(v => v.Id);
                if (vehicles.Any())
                {
                    Cache.Set("vehicles",vehicles,30);
                }
            }
            return vehicles.Values;
        }

        public void Update(Vehicle vehicle)
        {
            if (vehicle != null)
            {
                DataContext.Set().Attach(vehicle);
                DataContext.Entry(vehicle).State = EntityState.Modified;
            }
        }

        public void Insert(Vehicle vehicle)
        {
            DataContext.Set().Add(vehicle);
        }

        public void SaveChanges()
        {
            //获取上下文中EntityState状况为added或modified的Vehicle
             var changeobjects = DataContext.ChangeTracker.Entries();

            //把改变保留到数据库
            DataContext.SaveChanges();

            //更新缓存中有关的Vehicle
            var cacheData = Cache.Get("vehicles") as Dictionary<int, Vehicle>;
            if (cacheData != null)
            {
                foreach (var item in changeobjects)
                {
                    var vehicle = item.Entity as Vehicle;
                    cacheData[vehicle.Id] = vehicle;
                }
            }
        }
    }
}

 

在保留缓存Cache.Set("vehicles",vehicles,30)之前，把从上下文获取到的数据转换成IDictionary<int,t>类型vehicles = DataContext.Vehicle.ToDictionary(v => v.Id);

 

□ HomeController

using System.Linq;
using System.Web;
using System.Web.Mvc;
using MvcApplication1.Models;
using MvcApplication1.Repository;

namespace MvcApplication1.Controllers
{
    public class HomeController : Controller
    {
        public IVehicleRepository Repository { get; set; }

        public HomeController(IVehicleRepository repository)
        {
            this.Repository = repository;
        }

        public HomeController() : this(new VehicleRepository())
        {

        }
        public ActionResult Index()
        {
            return View(Repository.GetVehicles());
        }

        [HttpPost]
        public ActionResult Index(FormCollection form)
        {
            Repository.ClearCache();
            return RedirectToAction("Index");
        }

        public ActionResult Edit(int id)
        {
            var vehicle = Repository.GetVehicles().Single(v => v.Id == id);
            return View(vehicle);
        }

        [HttpPost]
        public ActionResult Edit(Vehicle vehicle)
        {
            Repository.Update(vehicle);
            Repository.SaveChanges();
            return RedirectToAction("Index");
        }

        public ActionResult Create()
        {
            return View(new Vehicle());
        }

        [HttpPost]
        public ActionResult Create(Vehicle vehicle)
        {
            Repository.Insert(vehicle);
            Repository.SaveChanges();
            return RedirectToAction("Index");
        }
    }
}

 

□ Home/Index.cshtml

@model IEnumerable

@{

    ViewBag.Title = "Index";

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

}

"0" cellspacing="0" border="0">

    @foreach (var vehicle in Model)

    {

    }

编号	车型	报价
@vehicle.Id.ToString()	@vehicle.Name	@string.Format("{0:c}",vehicle.Price)	@Html.ActionLink("修改", "Edit", new { id=vehicle.Id })

@using (Html.BeginForm())

{

    "submit" value="使缓存失效从头获取数据库数据" id="InvalidButton" name="InvalidButton"/>

}

 

    @Html.ActionLink("创立", "Create")

 

□ Home/Create.cshtml

@model MvcApplication1.Models.Vehicle @{ ViewBag.Title = "Create"; Layout = "~/Views/Shared/_Layout.cshtml"; }

Create

@using (Html.BeginForm()) {     @Html.ValidationSummary(true)Vehicle

class="editor-label"> @Html.LabelFor(model => model.Name)

class="editor-field"> @Html.EditorFor(model => model.Name) @Html.ValidationMessageFor(model => model.Name)

class="editor-label"> @Html.LabelFor(model => model.Price)

class="editor-field"> @Html.EditorFor(model => model.Price) @Html.ValidationMessageFor(model => model.Price)

value="Create" />

} @section Scripts { @Scripts.Render("~/bundles/jqueryval") }

 

□ Home/Edit.cshtml

@model MvcApplication1.Models.Vehicle @{ ViewBag.Title = "Edit"; Layout = "~/Views/Shared/_Layout.cshtml"; }

Edit

@using (Html.BeginForm()) { @Html.ValidationSummary(true)Vehicle@Html.HiddenFor(model => model.Id) 

class="editor-label"> @Html.LabelFor(model => model.Name)

class="editor-field"> @Html.EditorFor(model => model.Name) @Html.ValidationMessageFor(model => model.Name)

class="editor-label"> @Html.LabelFor(model => model.Price)

class="editor-field"> @Html.EditorFor(model => model.Price) @Html.ValidationMessageFor(model => model.Price)

value="Save" />

} @section Scripts { @Scripts.Render("~/bundles/jqueryval") }

 

□ 成果：

创立或修改之前： 

 

修改更新： 

 

创立： 

 

修改创立成功后： 

 

原文：http://www.codesocang.com/jiaocheng/MVCjiaocheng/2014/0408/7057.html