MVC 5 Route not found if parameter is passed in URL

I have following methods in my MVC controller:

[HttpGet] public ActionResult Add(Guid b) { ViewBag.Title="Add Location"; //init some info return View("Edit",<Model>); } [HttpGet] public ActionResult Edit(Guid l) { ViewBag.Title="Edit Location"; //get object from db return View("Edit",<Model>); } 

Following is the route registration:

routes.MapRoute( name: "Default", url: "{controller}/{action}/{id}", defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional } ); 

Now when I try to access following two routes:

1. http://localhost:60732/Location/Add?b=512f770f-51c3-4791-8eba-61fe753e2a83 2. http://localhost:60732/Location/Edit?l=512f770f-51c3-4791-8eba-61fe753e2a83 

First one works but 2nd gives 404.

I have also tried AttributeRouting with following routes:

[HttpGet] [Route("Location/AddLocation/{g}")] public ActionResult Add(Guid g) [HttpGet] [Route("Location/EditLocation/{l}")] public ActionResult Edit(Guid l) 

Again,

 http://localhost:60732/Location/AddLocation/512f770f-51c3-4791-8eba-61fe753e2a83 

works but

 http://localhost:60732/Location/EditLocation/512f770f-51c3-4791-8eba-61fe753e2a83 

does not.

What am I doing wrong?

Strangely, if I pass wrong Guid like:

 http://localhost:60732/Location/EditLocation/512f770f 

It gives following error:

The parameters dictionary contains a null entry for parameter 'l' of non-nullable type 'System.Guid' for method 'System.Web.Mvc.ActionResult Edit(System.Guid)' in 'AppointmentScheduler.Controllers.LocationController'. An optional parameter must be a reference type, a nullable type, or be declared as an optional parameter. Parameter name: parameters