MVC Routes - How to skip route rule if controller doesn't exist?

Question

I would like to be able to have custom pages that are not tied to a controller. These custom pages will all be routed to a default controller. Then there are other pages that are not custom that have Controller classes set up as normal. I can't get the routing rules to work for both situations.

I have routing rules that look like this:

    routes.MapRoute( _
        name:="Default", _
        url:="{controller}/{action}", _
        defaults:=New With {.controller = "Home", .action = "Index"} _
    )

    routes.MapRoute( _
         name:="Custom Page", _
         url:="{name}", _
         defaults:=New With {.controller = "Page", .action = "Index"} _
     )

This situation works for the static controllers, but not the custom pages. It always tries to find the controller with the custom name (url:="{name}") which doesn't exist, so I get a "Resource not found" error.

If I reverse the rules, then the custom pages work correctly, but the static pages do not.

I know that the problem is that both rules overlap each other, so whichever one is first is always used. Ideally I would like to be able to tell the routing to look for a controller named X, if it exists use that. If it doesn't exist, redirect to Y controller and pass in X as a parameter. Right now if the controller does not exist, it doesn't continue to the next routing rule, it just says the resource cannot be found.

Is something like this possible?

Answer 1

I have not tested this, but I think you may have to use {*name}, basically a catch all route as seen in this answer => .Net MVC Routing Catchall not working.

You would also need to switch your routes around so that the catch all is most specific, like so:

routes.MapRoute( _
     name:="Custom Page", _
     url:="{*name}", _
     defaults:=New With {.controller = "Page", .action = "Index"} _
 )

routes.MapRoute( _
    name:="Default", _
    url:="{controller}/{action}", _
    defaults:=New With {.controller = "Home", .action = "Index"} _
)

You also may need to use {*catchall} instead of {*name}, but I am not certain on that.

Answer 2

Here I Provide a solution for the problem. For each Route, you can define an alternative route, the alternative route will be used in case there is no controller for the route.

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

        var route = routes.MapRoute(
            name: "Dynamic",
            url: "{name}",
            defaults: new { controller = "Dynamic", action = "Index" });
        
        defaultRoute.AlternativeRoute = route;

The clue is in the latest line!