AcRxObject AcDbLayoutManagerReactor
class AcDbLayoutManagerReactor : public AcRxObject;
dblaymgrrctr.h
The AcDbLayoutManagerReactor class is used as the base class for reactor classes that override methods called for events for which notification is desired. When an object of one of these derived classes is instantiated and added to the reactor chain of the layout manager, then whenever layouts are manipulated via the layout manager, the appropriate methods within the reactor object will be called.
You use this class by defining a class that inherits from AcDbLayoutManagerReactor. You instantiate an object of the class derived from AcDbLayoutManagerReactor, and add the newly created reactor object to the reactor chain by calling the addReactor method of the layout manager.
AcDbLayoutManagerReactor Methods
AcDbLayoutManager, AcApLayoutManager