ASP.NET MVC Application_Error (404 handling) http://stackoverflow.com/questions/619895/how-can-i-properly-handle-404-in-asp-net-mvc/2577095#2577095 AND

Global.asax.cs

protected void Application_Error(object sender, EventArgs e)
{
    Exception exception = Server.GetLastError();
    HttpException httpException = exception as HttpException;

    // Log the exception.
    log.Info(String.Format("Application error: {0}:", exception));
    log.Info(exception.StackTrace);

    RouteData routeData = new RouteData();
    routeData.Values["controller"] = "Errors";
    routeData.Values["requestedUrl"] = Request.Url.OriginalString;

    if (httpException == null)
    {
        return; //We ignore the rest of the method
        //TODO: custom errors handling
        //routeData.Values.Add("action", "Index");
    }
    else
    {
        switch (httpException.GetHttpCode())
        {
            case 404:
                // Page not found.
                routeData.Values.Add("action", "Http404");
                break;

            default:
                return;
        }
    }


    HttpContext httpContext = ((MvcApplication)sender).Context;
    httpContext.Response.Clear();
    httpContext.Response.ContentType = "text/html";
    httpContext.Response.TrySkipIisCustomErrors = true;
    httpContext.Response.StatusCode = httpException != null ? httpException.GetHttpCode() : 500;
    Server.ClearError();

    // Call target Controller and pass the routeData.
    IController errorController = new ErrorsController();
    try
    {
        errorController.Execute(new RequestContext(new HttpContextWrapper(httpContext), routeData));
    }
    catch (Exception ex)
    {
        log.Info("Error in Global.asax: Application_Error():");
        log.Info(ex.StackTrace);

        string err = "<b>Error Caught in Global.asax: Application_Error() event</b><hr><br>" +
                "<br><b>Error in: </b>" + Request.Url.ToString() +
                "<br><b>Error Message: </b>" + ex.Message.ToString() +
                "<br><b>Stack Trace:</b><br>" + ex.StackTrace.ToString();
        Response.Write(err.ToString());
    }
}