aspnet vNext ActionFilter and TempData

Question

I'm trying to create an ActionFilter in aspnet vNext. Within this filter I want to access to the TempData and the ViewData (both available in Controller in previous versions).I override the method public override void OnActionExecuting(ActionExecutingContext filterContext)

Into the filterContext I have the controller but is an object instead of ControllerBase. I was expected a ControllerBase because in previous versions of MVC the ControllerContext (the base class of ActionExecutingContext) was a ControllerBase, here is the source code in codeplex. I understand that this could be because the POCO controllers.

So, the question is, how can access to the TempData and the ViewData if the controller is an object. Simply doing a downcasting (something like this (Controller)filterContext.Controller) or there's a best way to do it.

Update

That I want to achieve if explain it in this blog post but with aspnet 5.

Answer 1

To access TempData from within an action filter, you can get the service called ITempDataDictionary from DI.

To get this service from DI, you could either do something like actionContext.HttpContext.RequestServices.GetRequiredService<ITempDataDictionary>() from within your OnActionExecuting method. You could also use construction inject if you like by using ServiceFilterAttribute.

NOTE:
TempData by default depends on Session feature(i.e TempData's data is stored in Session) and so you need to few things to get it working.

• Reference Microsoft.AspNet.Session and Microsoft.Framework.Caching.Memory packages.

• In your ConfigureServices method, do the following:

  services.AddCaching();
  services.AddSession();
  

• In your Configure method, register the Session middleware (this is the one which creates/attaches a session to the incoming requests) and do it before registering MVC.

  app.UseSession();
  app.UseMvc(...)