Converting unsupported variant data types for use by visual LISP

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Question
My database field contains a Variant, which has ActiveX VarType as vbDate. For
example, the constant value is 14. How do I use the actual data value returned
from my database function ?
Answer
AutoLISP does not support all the Variant Data types made available to it though
the ActiveX COM inte**ce. For purposes of this solution, AutoLISP only supports
the following traditional types:
AutoLISP Reference -> type

Data type         Description
ENAME             Entity names
INT                   Integers
REAL                Floating-point numbers
STR                  Strings
SYM                  Symbols
In addition, AutoLISP supports these new data types for AutoCAD 2000:
SAFEARRAY       Safearray
VARIANT          Variant
VLA-object       ActiveX objects
(Please note that there are additional AutoLISP types listed in the
documentation.)

Several functions have been added to Visual Lisp for AutoCAD 2000 that will
assist you in converting from the Variant Data Type returned by ActiveX to
standard AutoLISP data types:
SAFEARRAY:
            (vlax-make-safearray type '(l-bound . u-bound)
            (vlax-safearray-fill var 'element-values)
            (vlax-safearray-get-dim var)
            (vlax-safearray-get-element var element...)
            (vlax-safearray-get-l-bound var dim)
            (vlax-safearray-get-u-bound var dim)
            (vlax-safearray-put-element var index... value)
            (vlax-safearray-type var)
            (vlax-safearray->list var)

VARIANT:
            (vlax-make-variant [value] [type])
            (vlax-variant-change-type var type)
            (vlax-variant-type var)
            (vlax-variant-value var)

VLA-object:
            (vlax-ename->vla-object entname)
            (vlax-vla-object->ename obj)
To convert from a Variant Data value, you could use a genericLISP function as in
the following code that  handles several variant data types, and converts the
variants into strings:

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The vlax-vbDate variant type is not a supported AutoLISP data type, but the code
converts the variant value directly into a string.

For more information on this topic, refer to the following sections of the
documentation:

Visual Lisp Developer's Guide -> Chapter 6 -- Working with ActiveX -> Using
Visual LISP Functions with ActiveX Methods -> Converting AutoLISP Data Types to
ActiveX Data Types -> Working with Variants

Visual Lisp Developer's Guide -> Chapter 6 -- Working with ActiveX -> Using
Visual LISP Functions with ActiveX Methods -> Converting AutoLISP Data Types to
ActiveX Data Types -> Converting Other AutoLISP Data Types for ActiveX Methods

See DevNote #53398 for additional AutoLISP code that demonstrates the
supported Variant Data Types and their values.
);odtoxd

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