ASP.NET MVC HandleError not working (customErrors is set to "On")

Question

I believe I have set up our MVC app to use [HandleError] properly. This is my controller:

[HandleError]
public class SupportController : BaseController {

    public ActionResult Toss() {
        throw new Exception("uh oh");
    }
    // snip
}

And I have set my customErrors tag in web.config to "On":

<customErrors mode="On"></customErrors>

However, I am still getting the Yellow Screen of Death on Exceptions. Setting a breakpoint in my Toss() action shows that HttpContext.IsCustomErrorEnabled is set to true.

We are not doing anything with the View Engine, and the BaseController doesn't mess with anything either (and other Controllers that do not extend it have the same issue).

I am developing on Windows XP, and have the same issue when the app is deployed to a server 2003 box (IIS 6).

I do not think there is an Exception on the error.aspx page:

<%@ Page Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage<System.Web.Mvc.HandleErrorInfo>" %>

<asp:Content ID="Content1" ContentPlaceHolderID="head" runat="server">
</asp:Content>

<asp:Content ID="errorContent" ContentPlaceHolderID="MainContent" runat="server">
    <h2>
        Sorry, an error occurred while processing your request.
    </h2>
</asp:Content>

One thing that may be different is that this app was created back when MVC Beta was the latest version, and was upgraded to the RC and then RTM as they were released. Might there have been some kooky setting that is left over from there?

I can get this working on other apps, so I'm a little flummoxed.

Answer 1

This tends to happen if there is a problem processing the error page.. if you debug the app, right after the initial exception you'll problem hit another (exception from the error page).. I had this happening and the reason for me was because I had a strongly typed master page, the error page was using this master page, and because the masterpage shares the same model as the actual page, the master page was getting a HandlerErrorInfo model, instead of the typed model I expected..

Personally I think this is a poor design in the asp.net mvc (along with the rest of it), but you can get around this easy enough by not using the same master page (you could even do masterpage inheritance where you have an inherited strongly typed master page that purely inherits the layer from the untyped one..

Otherwise this is some sort of exception happening in the error view.. (most likely).