Is it possible to clear route values with RedirectToAction?

Question

I want to redirect to an action in the same controller, but lose the route values (in particular, the id value). This is turning out to be surprisingly difficult. I have routes configured like this:

context.MapRoute(
    "Monitoring_controllerIdSpecified",
    "Monitoring/{controller}/{id}/{action}",
    new { action = "Status" }
);

context.MapRoute(
    "Monitoring_default",
    "Monitoring/{controller}/{action}",
    new { controller = "Events", action = "Index" }
);

... and an action method inside EventsController something like this:

public ActionResult Status(int id) {
    if (id > 1000) {
        TempData["ErrorMessage"] = "ID too high.";
        return RedirectToAction("Index", new { id = (int?)null });
    }

    // (code to display status)
}

If I then access something like /Monitoring/Events/1001, the RedirectToAction is indeed invoked, but I get redirected to /Monitoring?id=1001 instead of just /Monitoring. It seems to be matching the first route, Monitoring_controllerIdSpecified, even though that route has id as a mandatory route parameter and I told it to set id to null, and bizarrely turning id into a query string key. In other words, it is not properly clearing/removing the id route value. Setting id to an empty string in the routeValues object passed to RedirectToAction just gives the same effect as setting it to null.

Why is it doing this and how can I convince it not to match the first route because id has been completely removed from the route values?

Answer 1

Thanks to @Slicksim I found that the answer is to remove the key from RouteData.Values rather than setting it to null:

public ActionResult Status(int id) {
    if (id > 1000) {
        TempData["ErrorMessage"] = "ID too high.";
        RouteData.Values.Remove("id");
        return RedirectToAction("Index");
    }

    // (code to display status)
}