Application_Error event in global.asax not firing

Question

I'm having an issue where the Application_Error event does not seem to fire when I explicitly throw a page-level exception.

My Global.asax.cs file is as follow:

public class WebApiApplication : System.Web.HttpApplication
{
    protected void Application_Start()
    {
            AreaRegistration.RegisterAllAreas();
            WebApiConfig.Register(GlobalConfiguration.Configuration);
            FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
            RouteConfig.RegisterRoutes(RouteTable.Routes);
            BundleConfig.RegisterBundles(BundleTable.Bundles);
            CustomExceptionClass.BootstrapEnterpriseLibrary();  
    }

    // Event handler that passes all exceptions not in a catch statement 
    // to the handler

    protected void Application_Error(object sender, EventArgs e)
    {
        Exception ex = Server.GetLastError();
        CustomExceptionClass.HandleException(ex);
        Server.ClearError();
    }
}

public class ExceptionPublisherExceptionFilter : IExceptionFilter
{
    public void OnException(ExceptionContext exceptionContext)
    {
        var exception = exceptionContext.Exception;
        CustomExceptionClass.HandleException(exception);
    }
}

public class ErrorHandler : IErrorHandler
{
    public void ProvideFault(Exception error, MessageVersion version, 
        ref Message fault)
    {
    }

    public bool HandleError(Exception error)
    {
        CustomExceptionClass.HandleException(error);
        return true;
    }
}

My web.config file has <customErrors mode="Off">.

My filterconfig looks like the following:

public static void RegisterGlobalFilters(GlobalFilterCollection filters)
{
    filters.Add(new ExceptionPublisherExceptionFilter());
    //filters.Add(new HandleErrorAttribute());
}

I have tried the following fixes:

• Change customErrors to on or off
• Implement a new filter and add it to filterconfig

Whenever I throw an exception in VS, I try to step into it, but it just keeps on running. Does anyone know why Application_Error isn't being fired?

Edit: It looks like the scope affects whether Application_Error gets called. So the question is really, why Application_Error isn't being called at the page-level.

Answer 1

In case you were testing this with an HttpResponseException it turns out that those are ignored by ApiExceptionHandler and derived classes by design and will never result in Application_Error firing. Switch to another Exception type to address the issue.