Razor MVC, where to put global variables that's accessible across master page, partiview and view?

Question

Hello Razor MVC Gurus:

Newbie question.

Background. I have a custom IIdentity that is set in an HttpModule before it gets to controller &a

Answer 1

I'll explain a similar solution that works pretty well for me. With small changes, I believe that it will work for you (and others, hopefully) as well.

Basically, we'll be using inheritance.

Controllers

Let's create a custom base controller, such as

public class BaseController : Controller

and let's change our controllers to inherit from it, as

public class HomeController : BaseController

Models (ViewModels, I say)

You probably have lots of classes inside your Models folder, right? They act as DTOs from the controller to the views, right²? If you answered yes for both, then keep reading.

Let's create a base model class, such as public class BaseVM, and let's change our models to inherit from it, like public class HomeIndex : BaseVM

Important: your layout file (_Layout or whatsoever) must be strongly typed to BaseVM or a child of it.

The hook

Now that everything's beautifuly typed, let's use the request pipeline in our favor. At BaseController, you'll add a method that looks like this:

protected override void OnActionExecuted(ActionExecutedContext filterContext)
{
    if (filterContext.Result is ViewResultBase)//Gets ViewResult and PartialViewResult
    {
        object viewModel = ((ViewResultBase)filterContext.Result).Model;

        if (viewModel != null && viewModel is BaseVM)
        {
            BaseVM baseVM = viewModel as BaseVM;

            baseVM.MyIdentity = (MyIdentity)((GenericPrincipal)context.User).Identity;
            //and so on...
        }
    }

    base.OnActionExecuted(filterContext);//this is important!
}

OnActionExecuted is called after the execution of the action but before the view rendering. That's exactly what we want.

I hope you got it already. =)