Obtaining One Object Identifier from Another

AutoLISP Developer's Guide > Using the Visual LISP Environment > Working with ActiveX > Using Visual LISP Functions with ActiveX Methods > Converting Object References >

You may find the same drawing object represented by different identifiers and data types such as a handle string, an ename, a VLA-object, or an ObjectARX object ID integer. To obtain the identifier with the data type your program requires, use the following strategies:

To find the handle associated with an ename, use the DXF 5 group of the ename's association list:
_$ (setq handle-circle (cdr (assoc 5 (entget ename-circle))))

"4F"
To find the ename associated with a handle, use the handent function:
_$ (handent handle-circle)

<Entity name: 27f0538>
To find the VLA-object associated with a handle, use the vla-handleToObject function:
_$ (setq vla-circle (vla-handleToObject acadDocument

handle-circle))

#<VLA-OBJECT IAcadCircle 03642c24>
To find the handle associated with a VLA-object, use vla-get-handle to obtain the handle property:
_$ (vla-get-handle vla-circle)

"4F"
To find the ObjectARX object ID of a VLA-object, use vla-get-objectid to get the objectID property:
_$ (setq objid-Circle (vla-get-objectid vla-circle))

41878840
To find the VLA-object identified by an ObjectARX object ID, use the ObjectID-toObject method on the AutoCAD Document object:
_$ (vla-ObjectIDtoObject acadDocument objid-circle)

#<VLA-OBJECT IAcadCircle 03642c24>