Hi

Sounds like partial routing could be the way, see e.g. http://joelabrahamsson.com/custom-routing-for-episerver-content/ or http://world.episerver.com/Blogs/Johan-Bjornfot/Dates1/2012/11/Partial-Routing/

The example about Blog routing in the latter post could be useful. In that case the partial router returns the same page, that is if you still want to route to the same page. It uses extension method

segmentContext.SetCustomRouteData<T>
to set the partial routed data (in your case it would be the registration number).

You could then in the template get the value using:
HttpContext.Current.Request.RequestContext.GetCustomRouteData<T>

This seems the correct way, just can't figure out what exactly to put in the SetCustomRouteData. I have this setup:

The template page CarDetailsPageTemplate.aspx + .cs which inherits from CarDetailsPageBase

public class CarDetailsPageBase : PageBase
    {
        private static PageData _carDetailsPage;

        public static PageData CarDetailsPage
        {
            get
            {
                if (_carDetailsPage == null)
                {
                    _carDetailsPage = DataFactory.Get<PageData>((PageReference)StartPage["CarDetailsPage"]);
                }

                return _carDetailsPage;
            }
        }

        public static string CarRegistrationNumber { get; set; }
    }

The CarDetailsPartialRouter looks like this at the moment:

public class CarDetailsPartialRouter : IPartialRouter<CarDetailsPage, CarDetailsPageTemplate>
    {
        public object RoutePartial(CarDetailsPage content, SegmentContext segmentContext)
        {
            //Expected format is RegNumber/
            var regNumber = segmentContext.GetNextValue(segmentContext.RemainingPath);
            if (!String.IsNullOrEmpty(regNumber.Next))
            {

                segmentContext.SetCustomRouteData<CarDetailsPageTemplate>();
                return content;

            }

            return null;
        }

        public PartialRouteData GetPartialVirtualPath(CarDetailsPageTemplate content, string language, RouteValueDictionary routeValues, RequestContext requestContext)
        {
            return new PartialRouteData()
                {
                    BasePathRoot = CarDetailsPageBase.CarDetailsPage.PageLink,
                    PartialVirtualPath = String.Format("{0}/", CarDetailsPageBase.CarRegistrationNumber)
                };
        }
    }

What do I put in the SetCustomRouteData?

If registration number is the only thing you need, I guess it would be enough to set a string in the partial router like:

segmentContext.SetCustomRouteData<string>("regnumber", theRegnr);

And then in the template you would read out the routed reg nr as:

string regNr = HttpContext.Current.Request.RequestContext.GetCustomRouteData<string>("regnumber")

Note also that you should consume the segment (update RemainingPath) in the router if you handle the segment, that add the following line to your router:

segmentContext.RemainingPath = regNumber.Remaining

http://krompaco.nu/2013/11/partial-routing-with-epi-7-and-web-forms/

Yes got it all working now, so nice to be able to do this. Thanks for the input. Also found this article very helpful: http://world.episerver.com/Documentation/Items/Developers-Guide/EPiServer-CMS/7/Routing/Partial-Routing/Example-of-News-Partial-Routing/

Escpecially the InitalizationModule setup which I didn't really get from the start.