一、概述
IOC:英文全称:Inversion of Control,中文名称:控制反转,它还有个名字叫依赖注入(Dependency Injection)。
作用:将各层的对象以松耦合的方式组织在一起,解耦,各层对象的调用完全面向接口。当系统重构的时候,代码的改写量将大大减少。
依赖注入: 当一个类的实例需要另一个类的实例协助时,在传统的程序设计过程中,通常有调用者来创建被调用者的实例。然而采用依赖注入的方式,创建被调用者的工作不再由调用者来完成,因此叫控制反转,创建被调用者的实例的工作由IOC容器来完成,然后注入调用者,因此也称为依赖注入。
Unity是微软Patterns & Practices团队所开发的一个轻量级的,并且可扩展的依赖注入(Dependency Injection)容器;
它支持常用的三种依赖注入方式:构造器注入(Constructor Injection)、属性注入(Property Injection),以及方法调用注入(Method Call Injection)。
现在Unity最新的版本的4.0版,可以在微软的开源站点 https://github.com/unitycontainer/unity 下载最新的发布版本。
通过使用Unity,我们能轻松构建松耦合结构的程序,从而让整个程序框架变得清晰和易于维护。
二、简单示例
创建一个mvc5项目 Web.Mvc,然后在创建一个Business类库,将类库添加引用到Web.Mvc项目.
Business类库
类库代码
a、Business类库定义一个接口IUserService
namespace Business { /// <summary> /// 显示信息 /// </summary> public interface IUserService { string Display(string mes); } }
b、Business类库实现接口
namespace Business { public class UserService : IUserService { /// <summary> /// 显示信息 /// </summary> /// <param name="mes"></param> public string Display(string mes) { return "I say:" + mes; } } }
示例一
在Web.Mvc项目通过nuget添加unity.mvc5 (1.2.3)
1.注册服务
注册依赖使用依赖注入生效,在Web.Mvc项目的Global.asax进行注册
using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.Mvc; using System.Web.Optimization; using System.Web.Routing; using Business; using Microsoft.Practices.Unity; using Unity.Mvc5; namespace Web.Mvc { public class MvcApplication : System.Web.HttpApplication { protected void Application_Start() { AreaRegistration.RegisterAllAreas(); FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters); RouteConfig.RegisterRoutes(RouteTable.Routes); BundleConfig.RegisterBundles(BundleTable.Bundles); //注入 Ioc var container = this.BuildUnityContainer(); DependencyResolver.SetResolver(new UnityDependencyResolver(container)); } IUnityContainer BuildUnityContainer() { var container = new UnityContainer(); container.RegisterType<IUserService, UserService>(); return container; } } }
2.注入服务
namespace Web.Mvc.Controllers { public class HomeController : Controller { private IUserService userService; public HomeController(IUserService userService) { this.userService = userService; } public ActionResult Index() { ViewBag.Msg = userService.Display("hahaha"); return View(); } } }
e、在Index.cshtml找个地方写入@ViewBag.Msg 就可以,如
<h1>ASP.NET - @ViewBag.Msg</h1>
最后运行项目,实现效果
ASP.NET - I say:hahaha
示例二
本示例为2017.12.08补充。
创建一个mvc5项目 Web.Mvc,然后在创建一个Business类库,将类库添加引用到Web.Mvc项目,在Web.Mvc项目通过nuget添加unity.mvc5 (1.3.0)
命令:Install-Package Unity.Mvc5 -Version 1.3.0
安装后如图
1. 调用注册组件
在Global.asax.cs 的Application_Start 方法添加 UnityConfig.RegisterComponents() ,MVC会使用 Unity.Mvc5的 DependencyResolver去解析服务
protected void Application_Start() { AreaRegistration.RegisterAllAreas(); UnityConfig.RegisterComponents();//在此处添加 FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters); RouteConfig.RegisterRoutes(RouteTable.Routes); BundleConfig.RegisterBundles(BundleTable.Bundles); }
2.注册服务
找到App_Start下的UnityConfig类,如下修改
public static class UnityConfig { public static void RegisterComponents() { var container = new UnityContainer(); //在这里使用container注册所有服务 container.RegisterType<IUserService, UserService>();//自定义的服务 DependencyResolver.SetResolver(new UnityDependencyResolver(container)); } }
3.修改控制器Home和页面Index
public class HomeController : Controller { private IUserService userService; public HomeController(IUserService userService) { this.userService = userService; } public ActionResult Index() { ViewBag.Name = userService.Display("我是 UNITY 1.3.0"); return View(); }
页面代码
<div class="jumbotron"> <h1>Unity 入门</h1> <p class="lead">@ViewBag.Name</p> </div>
效果
三、注册封装
对示例一 的注册进行独立封装到BootStrapper中
c、注册依赖使用依赖注入生效
在Web.Mvc项目的Global.asax进行注册
using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.Mvc; using System.Web.Optimization; using System.Web.Routing; using Business; using Microsoft.Practices.Unity; using Unity.Mvc5; namespace Web.Mvc { public class MvcApplication : System.Web.HttpApplication { protected void Application_Start() { AreaRegistration.RegisterAllAreas(); FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters); RouteConfig.RegisterRoutes(RouteTable.Routes); BundleConfig.RegisterBundles(BundleTable.Bundles); //注入 Ioc BootStrapper.Initialise(); } } }
BootStrapper代码
using System; using System.Collections.Generic; using System.Configuration; using System.Linq; using System.Web; using System.Web.Mvc; using Business; using Microsoft.Practices.Unity; using Microsoft.Practices.Unity.Configuration; using Unity.Mvc5; namespace Web.Mvc { public class BootStrapper { /// <summary> /// 获取容器-注册依赖关系 /// </summary> /// <returns></returns> public static IUnityContainer Initialise() { var container = BulidUnityContainer(); DependencyResolver.SetResolver(new UnityDependencyResolver(container)); return container; } /// <summary> /// 加载容器 /// </summary> /// <returns></returns> private static IUnityContainer BulidUnityContainer() { var container = new UnityContainer(); RegisterTypes(container); return container; } /// <summary> /// 实施依赖注入 /// </summary> /// <param name="container"></param> private static void RegisterTypes(IUnityContainer container) { //类型的配置容器注册 container.RegisterType<IUserService, UserService>(); //container.RegisterType<IUserService, UserService>(new ContainerControlledLifetimeManager());//通过生命周期实现了单例模式 //已有对象实例的配置容器注册,也为单例 //UserService userService = new UserService(); //container.RegisterInstance<IUserService>(userService); } } }
Unity注册配置
修改上面的方法,将注册放到配置文件中
1.方法修改
/// <summary> /// 实施依赖注入 /// </summary> /// <param name="container"></param> private static void RegisterTypes(IUnityContainer container) { ////依赖关系可以选择代码形式,也可以用配置文件的形式 UnityConfigurationSection config = (UnityConfigurationSection)ConfigurationManager.GetSection(UnityConfigurationSection.SectionName); config.Configure(container, "defaultContainer"); }
UnityConfigurationSection.SectionName为unity
2.配置文件
提示:自定义web.config节点来实现
<configuration> <configSections> <section name="unity" type="Microsoft.Practices.Unity.Configuration.UnityConfigurationSection,Microsoft.Practices.Unity.Configuration"/> <!-- 一般将unity节点放到文件末尾 --> </configSections> <unity xmlns="http://schemas.microsoft.com/practices/2010/unity"> <namespace name="Business" /> <assembly name="Business" /> <containers> <container name="defaultContainer"> <register type="IUserService" mapTo="UserService"> <lifetime type="singleton" /> </register> <register type="ILocalUserService" mapTo="LocalUserService"/> </container> </containers> </unity> </configuration>
或者为
直接指定命名空间
<unity xmlns="http://schemas.microsoft.com/practices/2010/unity"> <assembly name="Business" /> <containers> <container name="defaultContainer"> <register type="Business.IUserService" mapTo="Business.UserService"> <lifetime type="singleton" /> </register> <register type="Business.ILocalUserService" mapTo="Business.LocalUserService"/> </container> </containers> </unity>
或者为
指定程序集名称
<unity xmlns="http://schemas.microsoft.com/practices/2010/unity"> <containers> <container name="defaultContainer"> <register type="Business.IUserService,Business" mapTo="Business.UserService,Business"> <lifetime type="singleton" /> </register> <register type="Business.ILocalUserService,Business" mapTo="Business.LocalUserService,Business"/> </container> </containers> </unity>
源码下载:https://gitee.com/zmsofts/XinCunShanNianDaiMa/blob/master/IocDemo.rar
参考网址:
http://www.cnblogs.com/zhangchenliang/archive/2013/01/08/2850970.html
https://www.lanhusoft.com/Article/108.html
http://blog.csdn.net/xingxing513234072/article/details/21176247
http://www.cnblogs.com/wwj1992/p/6728370.html
http://www.cnblogs.com/xishuai/p/3670292.html(推荐)