Code Red > AutoLISP (Vanilla / Visual)

Attribute replacer

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Shade:
I am trying to write a attribute value replacer, in visual lisp. The following is what I have come up with.


--- Code: ---(Defun ATTREPLACE (ENM ATT TXT)
  (setq OBJ (VLAX-ENAME->VLA-OBJECT ENM)
        ATT (VLA-GETATTRIBUTES OBJ)
        VAR (VLAX-VARIANT-VALUE ATT)
        CNT (vlax-safearray-get-dim VAR)     
  );
  (while (>= CNT 0)
   (setq ARG (VLAX-SAFEARRAY-GET-ELEMENT VAR CNT)
   CNT (- CNT 1)
   CHK (vlax-get-property ARG "TagString")
   )
   (if (= CHK ATT)
       (setq CNT 0
     VAL (vlax-put-property ARG "TextString" TXT)
       )
   );if
  );while 
);#ATTREPLACE
--- End code ---

The problemI am having, is I know a attribute exist in the block I pass to the lisp, but for some reason the lisp does not change the existing value to the new value.
The only reason I can figure out why is that the safety arrays dimension is 1 insetad of 6, which is the number of attributes I have in the block.

Why does (vlax-safearray-get-dim VAR) return 1 when there are 6 attributes in the block?
  :realmad:

T.Willey:
To get a list of attributes within a block, it is easier to use (vlax-invoke Obj 'GetAttributes).

Tim

whdjr:
Short and Sweet!

I like it T. :-)

Jeff_M:
Shade, while Tim's solution is far easier to work with, I'll attempt to answer your question.
A single dimension array is one with 1 column and multiple rows for the data. So the call to (vlax-safearray-get-dim VAR) returns 1 because there is just 1 column. To access what you thought you were you need to use the (vlax-safearray-get-l-bound VAR 1)...this is the lower index starting number of dimension(column) 1...and (vlax-safearray-get-u-bound VAR 1)...this is the upper value of dimension(column) 1 so if the lbound is 0 and the ubound is 5 you have 6 elements in that array's dimension.

And that is why using Tim's method is easier :)

Jeff_M:
Written on the fly, not tested but should work....this does what you are looking for

--- Code: ---(defun attreplace (enm att txt / atts )
  (setq obj (vlax-ename->vla-object enm)
        atts (vlax-invoke obj 'getattributes)
  );
  (foreach x atts
   (if (eq (vlax-get-property x "tagstring") att)
     (vlax-put-property x "textstring" txt)
     );if
  );foreach
);#attreplace
--- End code ---

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