ActionResult参数为null

Question

I have seen a couple related questions to this, but I cannot seem to solve my exact instance. I have a url such as http://127.0.0.1/UTS/Unit/J0000001 . That is, my controller is UTS , my action is Unit and there is an optional parameter c_number .

I have my route configured as follows:

  routes.MapRoute(
    name: "Unit",
    url: "{controller}/{action}/{c_number}",
    defaults: new { controller = "UTS", action = "Unit", c_number = "" }
  );

Then, my action in my controller as:

    public ActionResult Unit(string c_number)
    {
        UnitViewModel uvm = new UnitViewModel();
        uvm.unit = pacificRepo.Units.FirstOrDefault(g => g.c_number == c_number);
        uvm.geoLocation = pacificRepo.GeoLocations.FirstOrDefault(g => g.geo_location.Latitude == uvm.unit.geo_location.Latitude && g.geo_location.Longitude == uvm.unit.geo_location.Longitude);
        return View(uvm);
    }

Whenever I go to the example URL I gave above, c_number comes up as null . It should be J0000001 . Does anyone see something blatantly obvious that I'm missing?

Answer 1

Since you define it in your Route you don't need to add parameter for your c_number .You can get your value from RouteData dictionary.That c_number parameter has value only if you pass it as QueryString like http://someurl.com/UTS/Unit?c_number="J0000001"

public ActionResult Unit()
{
    var cNumber = RouteData.Values["c_number"].ToString();
}