NDIS Intermediate Driver: Can't bind to underlying miniport adapter

Hello all!

This is my first IM driver.
My driver startup successfully, anything needed in DriverEntry is
done.After that My ProtocolPnPEvent handler got NetEvent
NetEventReconfigure from NDIS with NULL ProtocolBindingContext, i do call
ReEnumerateBindings,then My ProtocolPnPEvent got NetEvent
NetEventBindsCompete twice,but NDIS does not call to
ProtocolBindAdapter.Why?
Thank you!!