MVC Controller构造器注入

UnityDependencyResolver 的标准写法
public class UnityDependencyResolver : IDependencyResolver
{
    private readonly IUnityContainer _unityContainer;
 
    public UnityDependencyResolver(IUnityContainer unityContainer)
    {
        _unityContainer = unityContainer;
    }
 
    public object GetService(Type serviceType)
    {
        return (serviceType.IsClass && !serviceType.IsAbstract) ||
            _unityContainer.IsRegistered(serviceType) ?
            _unityContainer.Resolve(serviceType) : null;
    }
 
    public IEnumerable GetServices(Type serviceType)
    {
        return (serviceType.IsClass && !serviceType.IsAbstract) ||
            _unityContainer.IsRegistered(serviceType) ?
            _unityContainer.ResolveAll(serviceType) : new object[] {};
    }
}
 
Global.asax
protected void Application_Start()最后加入下面代码
IUnityContainer container = new UnityContainer();
            container.RegisterType<IServiceA, ServiceA>();
            container.RegisterType<IServiceB, ServiceB>(); 
            container.RegisterType<IViewPageActivator, ViewPageActivator>();
            DependencyResolver.SetResolver(new UnityDependencyResolver(container));
MVC Controllerl里的定义（构造器函数注入实现）
public class HomeController : Controller
    {
        protected IServiceA _serviceA;
        protected IServiceB _serviceB;
        public HomeController(IServiceA serviceA, IServiceB serviceB)
        {
            _serviceA = serviceA;
            _serviceB = serviceB;
        }
        public ActionResult Index()
        {
            ViewBag.A = _serviceA.Say();
            ViewBag.B = _serviceB.Write();
            return View();
        }
    }