1.）在使用IOC之前误甚，先談?wù)勈裁词荌OC?
IOC是Inversion of Control的縮寫-“控制反轉(zhuǎn)”宪萄。

解耦圖.png

2.）如何通過IOC容器創(chuàng)建實例玖瘸？
IOC容器是通過反射進行創(chuàng)建實例，而對IOC的具體實現(xiàn)的框架有多種檀咙，當然也可以自己封裝一套自己的容器雅倒，而今天主要介紹的是Unity容器。
通過NuGet導入Unity包：

Unity包.png

創(chuàng)建一個Unity容器：
IUnityContainer unityContainer = new UnityContainer();
注冊對象：
//IPhone-抽象
//AndroidPhone-具體實現(xiàn)
unityContainer.RegisterType<IPhone, AndroidPhone>();
獲取對象的實例：
IPhone phone = unityContainer.Resolve<IPhone>();

3.）Unity生命周期
默認瞬時生命周期：每次返回都是一個新的對象弧可。

container.RegisterType<AbstractPad, ApplePad>(new TransientLifetimeManager());
AbstractPad Pad1 = container.Resolve<AbstractPad>();
AbstractPad Pad2 = container.Resolve<AbstractPad>();
Console.WriteLine(object.ReferenceEquals(Pad1, Pad2));

單例生命周期：每次返回都是同一個對象蔑匣。

container.RegisterType<AbstractPad, ApplePad>(new SingletonLifetimeManager());
AbstractPad pad1 = container.Resolve<AbstractPad>();
AbstractPad pad2 = container.Resolve<AbstractPad>();
Console.WriteLine(object.ReferenceEquals(pad1, pad2));

線程單例生命周期：同一個線程就只有一個實例，不同線程就是不同實例。

container.RegisterType<AbstractPad, ApplePad>(new PerThreadLifetimeManager());
AbstractPad pad1 = null;
AbstractPad pad2 = null;
AbstractPad pad3 = null;
Action act1 = new Action(() =>
{
    pad1 = container.Resolve<AbstractPad>();
    Console.WriteLine($"pad1由線程id={Thread.CurrentThread.ManagedThreadId}");
});
var result1 = act1.BeginInvoke(null, null);

Action act2 = new Action(() =>
{
    pad2 = container.Resolve<AbstractPad>();
    Console.WriteLine($"pad2由線程id={Thread.CurrentThread.ManagedThreadId}");
});
var result2 = act2.BeginInvoke(t =>
{
    pad3 = container.Resolve<AbstractPad>();
    Console.WriteLine($"pad3由線程id={Thread.CurrentThread.ManagedThreadId}");
    Console.WriteLine($"object.ReferenceEquals(pad2, pad3)={object.ReferenceEquals(pad2, pad3)}");
}, null);
act1.EndInvoke(result1);
act2.EndInvoke(result2);
Console.WriteLine($"object.ReferenceEquals(pad1, pad2)={object.ReferenceEquals(pad1, pad2)}");

4.)Unity通過配置文件進行注冊
配置文件代碼：

 <unity>
    <sectionExtension type="Microsoft.Practices.Unity.InterceptionExtension.Configuration.InterceptionConfigurationExtension, Unity.Interception.Configuration"/>
    <containers>
      <container name="testContainer1">
        <!--支持AOP-->
        <extension type="Interception"/>
        <register type="IOC.Interface.IPhone,IOC.Interface" mapTo="IOC.Service.ApplePhone, IOC.Service"/>
        <!--是dll名稱裁良，不是命名空間-->
        <!--接口多個實現(xiàn)別名獲取-->
        <register type="IOC.Interface.IPhone,IOC.Interface" mapTo="IOC.Service.AndroidPhone, IOC.Service" name="Android">
          <!--別名--> 
          <interceptor type="InterfaceInterceptor"/>
          <interceptionBehavior type="Common.AOP.LogBeforeBehavior, Common"/>
          <interceptionBehavior type="Common.AOP.LogAfterBehavior, Common"/>
          <interceptionBehavior type="Common.AOP.ParameterCheckBehavior, Common"/>
          <lifetime type="transient" /> 
        </register>
        <register type="IOC.Interface.IMicrophone, IOC.Interface" mapTo="IOC.Service.Microphone, IOC.Service"/>
        <register type="IOC.Interface.IHeadphone, IOC.Interface" mapTo="IOC.Service.Headphone, IOC.Service"/>
        <register type="IOC.Interface.IPower, IOC.Interface" mapTo="IOC.Service.Power, IOC.Service"/>
        <register type="IOC.Interface.AbstractPad, IOC.Interface" mapTo="IOC.Service.ApplePad, IOC.Service"/>
        <register type="IOC.IDAL.IBaseDAL, IOC.IDAL" mapTo="IOC.DAL.BaseDAL, IOC.DAL"/>
        <register type="IOC.IBLL.IBaseBll, IOC.IBLL" mapTo="IOC.BLL.BaseBll, IOC.BLL">
          <constructor>
            <param name="baseDAL" type="IOC.IDAL.IBaseDAL, IOC.IDAL"  />
            <param name="id" type="System.Int32" value="3" />
          </constructor>
        </register>
        <register type="IOC.IDAL.IDBContext`1, IOC.IDAL" mapTo="IOC.DAL.DBContextDAL`1, IOC.DAL"/>
      </container>
    </containers>
  </unity>

前臺創(chuàng)建實例：

ExeConfigurationFileMap fileMap = new ExeConfigurationFileMap();
fileMap.ExeConfigFilename = Path.Combine(AppDomain.CurrentDomain.BaseDirectory + "CfgFiles\\Unity.Config");//找配置文件的路徑
Configuration configuration = ConfigurationManager.OpenMappedExeConfiguration(fileMap, ConfigurationUserLevel.None);
UnityConfigurationSection section = (UnityConfigurationSection)configuration.GetSection(UnityConfigurationSection.SectionName);
IUnityContainer container = new UnityContainer();
section.Configure(container, "testContainer1");
//創(chuàng)建實例
IPhone phone = container.Resolve<IPhone>("Android");

5.）基于Unity擴展AOP：AOP面向切面編程應(yīng)用場景

在有了以上了解之后凿将，在去通過IOC容器創(chuàng)建控制器實例便清晰了
有參控制器，通過容器創(chuàng)建并構(gòu)造函數(shù)依賴注入

 public class ThirdController : Controller
{
          public IUserService _iUserService = null;
          public ICompanyService _iCompanyService = null;

          public ThirdController(IUserService userService, ICompanyService companyService)
          { 
                     _iUserService = userService;
                     _iCompanyService = companyService; 
           }
}

1.)重寫“默認控制器工廠”

public class CustomControllerFactory : DefaultControllerFactory
{
    protected override IController GetControllerInstance(RequestContext requestContext, Type controllerType)
   {
        //要通過容器來創(chuàng)建控制器實例  得先得到容器
        //1. 獲取容器,并將后期依賴進行注冊
        IUnityContainer container = DIFactory.GetContainer();
        //2.通過容器創(chuàng)建控制器實例价脾，根據(jù)實例類型牧抵，查找實例構(gòu)造函數(shù)所需要的依賴項，
        //通過容器內(nèi)的對象進行注入侨把，若在容器內(nèi)無法找到則無法實例該對象
        return (IController)container.Resolve(t: controllerType);       
    }
    public override IController CreateController(RequestContext requestContext, string controllerName)
    {
        return base.CreateController(requestContext, controllerName);
    }
}

2.)替換“默認控制器工廠”
Global.asax

  //用自定義的控制器工廠替換掉MVC框架中默認的控制器工廠
  ControllerBuilder.Current.SetControllerFactory(new RichardControllerFactory());

經(jīng)過上述的過程犀变，