Using tblobjname to alter the layer color

By Xiaodong Liang

Issue
I'm trying to use entmod to update the color of a layer, but I cannot get this code to work:

(defun WrongChgLyrClr (laynme layclr / tb3 tb4)
  (if (tblsearch "LAYER" laynme)
    (progn
     (setq tb3 (tblsearch "LAYER" laynme))
     (setq tb4 (subst (cons 62 layclr) (assoc '62 tb3) tb3))
     (if
       (entmod tb4)
         (princ (strcat "\nLayer Color Updated to: " (itoa layclr)))
         (princ "\nLayer Color Was NOT Updated.")
     )
      )
    (princ (strcat "\nLayer: " " was NOT found !"))
  )
 (princ)
)
; (WrongChgLyrClr "CIRCLES" 4)

What am I doing wrong ?

Solution
In order to update the color assigned to a layer you'll need to use the entity list obtained from the entity name returned by the (tblobjname) function, and not the list returned by the tblsearch or tblnext functions. The entmod function will only update the layer with the entity list obtained via the tblobjname entity.

(defun ChgLyrClr (laynme layclr / tb3 tb4)
  (if (tblsearch "LAYER" laynme)
    (progn
     (setq tb3 (entget (tblobjname "LAYER" laynme)))
     (setq tb4 (subst (cons 62 layclr) (assoc '62 tb3) tb3))
     (if
       (entmod tb4)
         (princ (strcat "\nLayer Color Updated to: " (itoa layclr)))
         (princ "\nLayer Color Was NOT Updated.")
     )
    )
    (princ (strcat "\nLayer: " " was NOT found !"))
  )
 (princ)
)

; (ChgLyrClr "CIRCLES" 7)
(princ "\nChgLyrClr loaded, type (ChgLyrClr \"ALayerName\" (setq aLayerColor 7))
to run.")
(princ)