Using the code from // http://resources.arcgis.com/en/help/arcobjects-net/conceptualhelp/index.html#//0001000004m0000000, I created ESRI.ArcGIS.Location.IDatabaseLocatorWorkspace. Using the code below, I opened a feature class IWorkspace ws = LocWS.Workspace; // LocWS - ESRI.ArcGIS.Location.IDatabaseLocatorWorkspace IFeatureWorkspace fWs = (IFeatureWorkspace)ws; IFeatureClass fClass = fWs.OpenFeatureClass(fName); Then, I need to cast the feature class as a ESRI.ArcGIS.Location.RouteMeasureLineLocationClass. However, from the ArcObjects diagram, I can't get any hint how to do it. Do you have any idea how to cast a FeatureClass as ESRI.ArcGIS.Location.RouteMeasureLineLocationClass? Thanks.