Question

Using ASP.NET MVC3.

What I’m trying to do is initialize a Controller field/property with an Application state variable.

I.e. in my Application_Start() method I have

Application["stats"] = new Stats(); //this is fine

Accessing this via a Controller method, e.g.

public ActionResult Index()
{
  return View(HttpContext.Application["stats"]); //this is also fine
}

works fine too.

//blows up with a 'Object reference not set to an object' error.
private Stats stats;
public HomeController()
{
    stats= (Stats)(HttpContext.Application["stats"]);
}

Anyone able to explain what I’m failing to understand + how to go about fixing the problem ? If there’s a better way, let me know (and just in case you’re wondering, I’m not trying to load up application configuration or anything; just to keep live stats on the state of the website)

Thanks in advance

-Marcin

Answer 1

The HttpContext is not yet initialize inside a controller constructor and is null.

If you need to access any HttpContext related stuff this could be done at most early inside the Initialize method:

public class HomeController: Controller
{
    private Stats stats;

    protected override void Initialize(RequestContext requestContext)
    {
        base.Initialize(requestContext);
        stats = (Stats)(HttpContext.Application["stats"]);
    }
}