redirectToAction results in null model - asp.net-mvc

Question

I have 2 actions on a controller:
public class CalculatorsController : Controller
{
//
// GET: /Calculators/
public ActionResult Index()
{
return RedirectToAction("Accounting");
}
public ActionResult Accounting()
{
var combatants = Models.Persistence.InMemoryCombatantPersistence.GetCombatants();
Debug.Assert(combatants != null);
var bvm = new BalanceViewModel(combatants);
Debug.Assert(bvm!=null);
Debug.Assert(bvm.Combatants != null);
return View(bvm);
}
}
When the Index method is called, I get a null model coming out. When the Accounting method is called directly via it's url, I get a hydrated model.

Answer 1

This is less an answer than a workaround. I am not sure why you are getting a null model as it looks like it should work. In fact, I can confirm the behavior you are seeing when I try it out myself. [EDIT: I discovered a flaw in my initial test code that was causing my own null model. Now that that is corrected, my test works fine using RedirectToAction.] If there is a reason for it, I don't know it off the top of my head.
Now for the workaround...I assume that you are doing it this way since the default route sends all traffic to http://www.domain.com/Calculators to "Index". So why not create a new route like this:
routes.MapRoute(
"Accounting",
"Calculators/{action}/",
new { controller = "Calculators", action = "Accounting" }
);
This route specifies the default action to the Calculators controller will be "Accounting" instead of Index.

Answer 2

Your view for the Action Accounting expects a model. (the BalanceViewModel). The index action method does not have a instance of the BalanceViewModel.
There are a number of ways you can solve this. In your View (aspx page) you can check for nulls...
Or in the index action method, you create a new instance of a BalanceViewModel and store it in TempData, and then retrieve this in your view when your model is null.
Or in your action method, you could also call return View("Accounting", new BalanceViewModel()) instead of using redirect to action.
EDIT: Example Code -
If you want to share this functinality, create a private method like this:
public class CalculatorsController : Controller {
// GET: /Calculators/
public ActionResult Index() {
return View(GetBalanceViewModel());
}
public ActionResult Accounting() {
return View(GetBalanceViewModel());
}
private BalanceViewModel GetBalanceViewModel() {
var combatants = Models.Persistence.InMemoryCombatantPersistence.GetCombatants();
Debug.Assert(combatants != null);
var bvm = new BalanceViewModel(combatants);
Debug.Assert(bvm != null);
Debug.Assert(bvm.Combatants != null);
return bvm;
}
}
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