protected void OnViewChanged(ViewChangedEventArgs args)
 {
     if (ViewChanged != null)
     {
         ViewChanged(this, args);
     }
 }
 public virtual void InterestTargetChanged(object sender, PositionedObjectChangedEventArgs e)
 {
     // Do internal stuff.
     ViewChangedEventArgs args = new ViewChangedEventArgs();
     PositionedObjectChange ch = new PositionedObjectChange();
     ch.objectId = ((PositionedObject)sender).Id;
     args.change = ch;
     OnViewChanged(args);
 }