public TrckCtnrCtrl(ITrackableCtrl tracker)
{
InitializeComponent();
if (tracker == null)
throw new ArgumentNullException("tracker");
_mTracker = tracker;
this.xMainGrid.Children.Add(tracker.TrackableCtrl);
}
void IGrpPrgTracker.AddChildTracker(ITrackableCtrl tracker)
{
_mTrackableList.Add(tracker.Id, tracker);
}