How to get main controller and action names from partial view action - asp.net-mvc

Question

I have a controller:
public class LanguageController : Controller
{
[HttpGet]
public ActionResult Index()
{
// populate viewModel from database
return PartialView(viewModel)
}
[HttpPost]
public ActionResult Index(string language)
{
LanguageCookie.Write(Response, language);
return RedirectToAction(ACTION, CONTROLLER, new {culture = language});
}
}
and its partial view:
#model MyModel
#using (Html.BeginForm("Index", "Language"))
{
#Html.DropDownList(
Model.SelectedLanguageShortName,
Model.AllLanguages
)
<input type="submit" value="Select" />
}
which I render in _Layout.cshtml:
<div>
#Html.Action("Index", "Language")
</div>
Please let me know how can I get ACTION/CONTROLLER names of main (not partial) controller, from my LanguageController was called. I need this information on the postback where I set cookie and want to redirect user on the same page but with prefered language.
I have found this example:
var rd = ControllerContext.ParentActionViewContext.RouteData;
var currentAction = rd.GetRequiredString("action");
var currentController = rd.GetRequiredString("controller");
But ControllerContext.ParentActionViewContext is null in the postback. I am able to get what I need in the view but it is ugly:
#Html.Hidden("Controller", HttpContext.Current.Request.RequestContext.RouteData.Values["controller"].ToString());
#Html.Hidden("Action", HttpContext.Current.Request.RequestContext.RouteData.Values["action"].ToString());
How to get the same information in the controller scope?

Answer 1

When Index(string language) is processed ParentActionViewContext is null because this is another request to server and it doesn't know anything about previous request that invoked child action.
Instead of storing control and action in hidden field you can store the whole address and invoke Redirect:
#model MyModel
#using (Html.BeginForm("Index", "Language", new { redirectUrl = Request.Url }))
{
#Html.DropDownList(
Model.SelectedLanguageShortName,
Model.AllLanguages
)
<input type="submit" value="Select" />
}
and then
[HttpPost]
public ActionResult Index(string language, string redirectTo)
{
LanguageCookie.Write(Response, language);
return Redirect(redirectTo);
}
Another way is to save CONTROLER and ACTION in TempData, but in this way you can have problem if somebody open multiple pages of your site.
Third solution is to invoke that method with Ajax and when response arrive reload the page with javascript.