Custom Class Derivation

To facilitate development, custom classes should be declared and implemented in a separate ObjectDBX ^™ module, which is called an Object Enabler. The Object Enabler should contain the database portion of your application, including the AcRxObject macros described in this section and the functions overriden from other ObjectARX classes as well as the functions specific to your custom class. Because it is an ObjectDBX module, an Object Enabler may not use the AutoCAD ^® editor, editor reactors, or any other APIs specific to the AutoCAD host application. See Object Enablers for details.

ObjectARX provides a set of macros, declared in the rxboiler.h file, that helps you create new classes derived from AcRxObject. If you do not use the ObjectARX macros to define your new class, the class will inherit the runtime identity of its most immediate ObjectARX-registered parent class.

Note: Custom classes cannot inherit from more than one registered ObjectARX class. However, you can use multiple inheritance as long as only one of the base classes is part of the ObjectARX class tree.

Applications should not derive classes from the following:

• AcDb2dPolyline
• AcDb2dVertex
• AcDb3dPolyline
• AcDb3dPolylineVertex
• AcDbBlockBegin
• AcDbBlockEnd
• AcDbDimension
• AcDbFaceRecord
• AcDbMInsertBlock
• AcDbPolygonMesh
• AcDbPolygonMeshVertex
• AcDbPolyFaceMesh
• AcDbPolyFaceMeshVertex
• AcDbSequenceEnd
• AcDbSurface and all derived classes
• AcDbSymbolTable, AcDbSymbolTableRecord, and all classes derived from them
• AcDbVertex
• AcDbViewport