Question

Im converting a webforms app to mvc 4. The app does a fair amount of processing in the master page codebehind to do stuff such as determine what the user can or cant see based on their role, display a version at the bottom of the page from the assembly, etc. All server side.

I get that the processing isnt in a codebehind, but in a controller with the data sent to the view. But its not clear to me how this is done in the _Layout.cshtml

Thanks very much

Answer 1

Something you might be able to do is to use a base controller and override the OnActionExecuting method and then use the ViewBag dynamic property to pass values to your _Layout.cshtml

public abstract class BaseController : Controller
{
   protected override void OnActionExecuting(ActionExecutingContext filterContext)
   {
      var user = filterContext.Controller.ControllerContext.RequestContext.HttpContext.User;
      // do whatever you need to do
      ViewBag.CanUserViewSomethingSecret = user.Identity.Name == "Kermit";
   }
}

You’d need to extend this base controller with application controllers

public class HomeController : BaseController 
{
    public ActionResult Index()
    {
        return View();
    }
}

Then in your _Layout.cshtml you can access the ViewBag property like so…

   @if(ViewBag.CanUserViewSomethingSecret != null && (bool) ViewBag.CanUserViewSomethingSecret == true) 
   {
       <p>Secret</p>
   }