Partial Routing in EPiServer dealing with extra Route data.

epiPartialRouting.cs

public class NewsListPartialRouting : IPartialRouter<NewsListPage, NewsListPage>
    {
        public object RoutePartial(NewsListPage content, SegmentContext segmentContext)
        {
            var nextSegment = segmentContext.GetNextValue(segmentContext.RemainingPath);
            var urlSegment = nextSegment.Next;
            if (string.IsNullOrEmpty(urlSegment))
            {
                return null;
            }

            segmentContext.RemainingPath = nextSegment.Remaining;
            segmentContext.RoutedContentLink = content.ContentLink;

            int page;
            if(!int.TryParse(urlSegment, out page))
            {
                return content;
            }
            segmentContext.RouteData.Values["page"] = page;
            return content;
        }

        public PartialRouteData GetPartialVirtualPath(NewsListPage content, string language, RouteValueDictionary routeValues,
                                                      RequestContext requestContext)
        {
            var contentLink = ContentRoute.GetValue("node", requestContext, routeValues)
                      as ContentReference;

            if (!content.ContentLink.CompareToIgnoreWorkID(contentLink))
            {
                return null;
            }

            if (PageEditing.PageIsInEditMode)
            {
                return null;
            }

            return new PartialRouteData
            {
                BasePathRoot = content.ContentLink,
                PartialVirtualPath = content.URLSegment
            };
        }
    }