public Geometry Geometry {get;}

{
  // Note: Needs QueuedTask to run
  {
    if (tinLayer.CanGetZs())
    {
      // get z value for a mapPoint
      var zResult = tinLayer.GetZs(mapPoint);
      if (zResult.Status == SurfaceZsResultStatus.Ok)
      {
        // cast to a mapPoint
        var mapPointZ = zResult.Geometry as MapPoint;
        var z = mapPointZ.Z;
      }

      // get z values for a polyline
      zResult = tinLayer.GetZs(polyline);
      if (zResult.Status == SurfaceZsResultStatus.Ok)
      {
        // cast to a Polyline
        var polylineZ = zResult.Geometry as Polyline;
      }
    }
  }
}