That's a Silverlight Viewer library, so might be better to post the question of the Viewer forum.
OK, cool. Never used that library before.
ESRI.ArcGIS.Client.Extensibility
Are you sure that is an ArcGIS API for Silverlight property?
MapApplication.Current.SelectedLayer will get you there.
Les membres connectés peuvent publier, suivre les mises à jour, et plus encore. Nouveau ici ? Inscrivez-vous gratuitement.
Find useful guides, FAQs, and documents to help you navigate and make the most of Esri Community.