Change Attributes, changes all blocks.

This code is driving me silly..

(defun mm-put-entity-att-value
(Block-Ent TagString Textstring / Block-Set Block-Entity Block-Next
cnt)
(setq Block-Next Block-Ent)
(while (setq Block-Next (entnext Block-Next))
(if (= (dxf 0 (setq Block-Entity (entget Block-Next))) "ATTRIB")
(if (= (dxf 2 Block-Entity) TagString)
(progn
(entmod (subst (cons 1 Textstring) (assoc 1 Block-Entity)
Block-Entity))
(entupd Block-Ent)
)
)
)
)
)

I use it to select a single block, ie my material list, which is the same
block inserted many times. I change on Block-Ent which is pass a ename, but
several of the blocks are updated, sometimes all, but not always. Does
anyone know what I doing wrong ??

 

Dont worry to much folks, sorted it with ActiveX.

(defun mm-put-entity-att-value
(Block-Ent TagString Textstring / Block-Set Block-Entity Block-Next
cnt)
(setq
Attribute-list (vlax-safearray->list
(vlax-variant-value (vla-getattributes (vlax-ename->vla-object
Block-Ent)))
) ;_ end of vlax-safearray->list
) ;_ end of setq
(foreach Attribute Attribute-List
(if
(= TagString (vla-get-TagString Attribute))
(setq Attribute-Value (vla-put-TextString Attribute Textstring))
)
)
)


Thanks anyway