ASP.Net MVC 3 Unity IoC Disposal

Question

I am developing an ASP.Net MVC 3 Web application which uses Unity 2.0 as it's IoC container.

Below shows an example of my Application_Start() method in my Global.asax file

protected void Application_Start()
{
    AreaRegistration.RegisterAllAreas();

    RegisterGlobalFilters(GlobalFilters.Filters);
    RegisterRoutes(RouteTable.Routes);
    IUnityContainer container = new UnityContainer();

    container.RegisterType<IControllerActivator, CustomControllerActivator>(
        new HttpContextLifetimeManager<IControllerActivator>());

    //container.RegisterType<IUnitOfWork, UnitOfWork>(
    //  new ContainerControlledLifetimeManager());
    container.RegisterType<IUnitOfWork, UnitOfWork>(
        new HttpContextLifetimeManager<IUnitOfWork>());

    container.RegisterType<IListService, ListService>(
        new HttpContextLifetimeManager<IListService>());
    container.RegisterType<IShiftService, ShiftService>(
        new HttpContextLifetimeManager<IShiftService>());

    DependencyResolver.SetResolver(new UnityDependencyResolver(container));
}

My HttpContextLifetimeManager looks like this

public class HttpContextLifetimeManager<T> : LifetimeManager, IDisposable
{
    public override object GetValue()
    {
        return HttpContext.Current.Items[typeof(T).AssemblyQualifiedName];
    }

    public override void RemoveValue()
    {
        HttpContext.Current.Items.Remove(typeof(T).AssemblyQualifiedName);
    }

    public override void SetValue(object newValue)
    {
        HttpContext.Current.Items[typeof(T).AssemblyQualifiedName] =
            newValue;
    }

    public void Dispose()
    {
        RemoveValue();
    }
}

My issue is that, the method Dispose() in the above class is never called when I put a breakpoint on it. I am worried that my IoC container instance is never being disposed of. Could this lead to problems?

I found this snippet of code which I placed in my Global.asax file, but still the Dispose() method never gets called

protected void Application_EndRequest(object sender, EventArgs e)
{
    using (DependencyResolver.Current as IDisposable);
}

Can anyone help me with how to dispose of each instance of my Unity container?

Thanks.

Adam Tuliper - MSFT Adam Tuliper - MSFT · Accepted Answer · 2012-07-26T16:40:25

Use the Unity.MVC3 nuget package. Then when initializing specify the HierarchicalLifetimeManager and your objects will be disposed of after each request.

container.RegisterType(new HierarchicalLifetimeManager());

It's as simple as that : )

ASP.Net MVC 3 Unity IoC Disposal

2 Answers