Help me Example Reactor- Visual lisp

I'm learning Reactor. I want to use reactor for ATT Block.

In found in help: vlr-object-reactor -> :vlr-subObjModified

but don't have any Example about :vlr-subObjModified

Thanks.

Example:

(defun c:Start_Object_Reactor nil

 (if (not (vl-position "ATT-REACT"
            (mapcar
              (function
                (lambda (x)
                  (strcase
                    (vlr-data x))))
              (cdar (vlr-reactors :vlr-object-reactor)))))

   (if (and (princ "\n Select Objects to Trigger Reactor: ")
            (setq i -1 ss (ssget '((0 . "INSERT") (66 . 1)))))
     (progn

       (while (setq ent (ssname ss (setq i (1+ i))))
         (setq OwnerList (cons (vlax-ename->vla-object ent) OwnerList)))
   
       (vlr-object-reactor OwnerList "Att-React"
         (list
           (cons :vlr-subobjmodified 'DoIt)))))

   (princ "\n** Object Reactor Already Running **"))

 (princ))


(defun DoIt (Object Reactor Args)
 (alert
   (strcat "You Modified an Attribute in Block: "
           (vl-prin1-to-string Object)))
 (princ))


(defun c:End_Object_Reactor (/ React)

 (if (and (setq React
            (vl-some
              (function
                (lambda (x)
                  (if (eq "ATT-REACT"
                          (strcase (vlr-data x))) x)))
              (cdar (vlr-reactors :vlr-object-reactor))))
          (vlr-added-p React))

   (vlr-remove React)
   (princ "\n** Reactor Not Running **"))

 (princ))
 

   

   

thanks Lee.

I have 2 attriblock.

attriblock1 have: Tag1 ->string1

attriblock2 have: Tag2 ->string2

I want always string1 = string2.

Help me code in function "DO IT"

vlr-object-reactor OwnerList "Att-React"

(list

(cons :vlr-subobjmodified 'DoIt)))))

Hi Lee,

This is about what I need, but why does the alert fire once for each attribute in the block when I only change one or none and then use ok ?

If canceled it does not fire the alert.

my code in the Doit part only needs to happen once each time the block is accessed and modified.

Thanks

roby