Mixed SimpleInjector image for every web request and lifespan

I am using Simple Injector as my IoC container and am using the following method to register a "mixed" lifestyle for some objects both per web request and per thread.

interface IUnitOfWork { }
interface IWebUnitOfWork : IUnitOfWork { }
interface IThreadUnitOfWork : IUnitOfWork { }
class UnitOfWork : IWebUnitOfWork, IThreadUnitOfWork { }

container.RegisterPerWebRequest<IWebUnitOfWork, UnitOfWork>();
container.RegisterLifetimeScope<IThreadUnitOfWork, UnitOfWork>();
container.Register<IUnitOfWork>(() => container.GetInstance<UnitOfWork>());

// Register as hybrid PerWebRequest / PerLifetimeScope.
container.Register<UnitOfWork>(() =>
{
    if (HttpContext.Current != null)
        return container.GetInstance<IWebUnitOfWork>() as UnitOfWork;
    else
        return container.GetInstance<IThreadUnitOfWork>() as UnitOfWork;
});

      

        
        
        
      

    

I am not completely satisfied with this solution as for each requirement I have to define additional empty interfaces to make it work and to ensure that they refer to my specific class.

Is there a reason I shouldn't use the following extension methods instead of defining additional interfaces? If there is any problem with these methods, is there another way to establish with complete confidence that my current container instance is running in IIS?

public static void RegisterHybridLifestyle<TService, TImplementation>(
    this Container container)
    where TService : class
    where TImplementation : class, TService
{
    if (System.Web.Hosting.HostingEnvironment.ApplicationHost != null)
        container.RegisterPerWebRequest<TService, TImplementation>();
    else
        container.RegisterLifetimeScope<TService, TImplementation>();
}

public static void RegisterForLifestyle<TConcrete>(
    this Container container)
    where TConcrete : class
{
    if (HostingEnvironment.ApplicationHost != null)
        container.RegisterPerWebRequest<TConcrete>();
    else
        container.RegisterLifetimeScope<TConcrete>();
}

      

        
        
        
      

    

UPDATE

The above question and this follow up on the question were based on a misunderstanding of SimpleInjector and hybrid registration. The techniques described above and elsewhere on SO refer to when a container can serve a request for both web requests and background processes that are not running in the context of a web request. What I have been trying to achieve is registering variables to serve container configuration which is appropriate for both web request OR request . those. I need to configure my container to run on IIS and run on a windows service. I don't need a dynamic registration that can serve the same time at the same time.

This results in the following extension methods and I removed the "redundant" interfaces from my solution :-)

public static void RegisterForScope<TService, TImplementation>(this Container container)
    where TService : class
    where TImplementation : class, TService
{
    if (System.Web.Hosting.HostingEnvironment.ApplicationHost != null)
        container.RegisterPerWebRequest<TService, TImplementation>();
    else
        container.RegisterLifetimeScope<TService, TImplementation>();
}

public static void RegisterForScope<TConcrete>(this Container container)
    where TConcrete : class
{
    if (System.Web.Hosting.HostingEnvironment.ApplicationHost != null)
        container.RegisterPerWebRequest<TConcrete>();
    else
        container.RegisterLifetimeScope<TConcrete>();
}