Chen,
>>Without NavControl:
This is correct, because if you haven't specified the grid as your navigation control, then the navigation events don't get fired properly.
>>With NavControl:
In this scenario, the navigation events are firing properly in the parent, and the child is receiving and responding to events. In order for a grandchild object to respond, you need to put code in the HookParentNavigated event of the child object that will in turn fire an event in the grandchild object.
Regards,
Kevin McNeish
Eight-Time .NET MVP
VFP and iOS Author, Speaker & Trainer
Oak Leaf Enterprises, Inc.
Chief Architect, MM Framework
http://www.oakleafsd.com