Detect Circular Xref in AutoLISP

[Ahankhah]

Hi,
I need to check in AutoLISP whether an attached Xref in the current drawing creates a circular reference (refers to itself or a parent Xref).

Is there a way, using AutoLISP or ActiveX, to detect this before attaching or reloading the Xref?

Ideally, a function that takes the Xref name and returns True/False for circular reference.

Any sample code or approach would be greatly appreciated.

[mhupp]

Use CLASSICXREF will display a window for you to look thought. for the ones that you suspect to be circular switch to overlay.

[Steven P]

AutoCAD is very bad at running a LISP in one file to read another file, it is not something I have looked at with xrefs, however this might give you a starter, listing any xrefs in the current file - I was looking at this to do something different and is in the folder "finish this one day"... so the code might not be 100%.

 

;;https://forums.autodesk.com/t5/visual-lisp-autolisp-and-general/grab-all-xref-names-and-paths/td-p/1661552
;;(defun filepfil ( / Doc LayoutCol EndList)
;; Returns a list of list of all the Xrefs and Images with their paths within a drawing.

(defun c:xreffilepaths ( / )
  (defun xreftype ( str / )
;;    (setq lst (list "abcd.dwg" "1234.dwg" "sample drawing with space in file name.dwg" "5566.dwg") )
;;    (mapcar '(lambda (x)
;;        (substr x 1 (- (strlen x) 4))
;;      )
;;      lst
;;    )
  (setq MyLen (strlen str))
  (setq MyType (substr str (- MyLen 3) ))
  )




  (setq Doc (vla-get-ActiveDocument (vlax-get-Acad-Object)))
  (setq LayoutCol (vla-get-Layouts Doc))
  (vlax-for i LayoutCol
    (vlax-for Obj (vla-get-Block i)
      (cond
        ((= (vla-get-ObjectName Obj) "AcDbRasterImage")
        (if (not (assoc (vla-get-Name Obj) EndList))
          (setq EndList (cons (cons (vla-get-Name Obj) (vla-get-ImageFile Obj)) EndList))
      )
    )
    ((and (= (vla-get-ObjectName Obj) "AcDbBlockReference")
    (vlax-property-available-p Obj 'Path))
      (if (not (assoc (vla-get-Name Obj) EndList))
        (setq EndList (cons (cons (vla-get-Name Obj) (vla-get-Path Obj)) EndList))
          )
        )
      )
    )
  )
  EndList


(princ "\nContains Xrefs: ")
(princ EndList)
(foreach n EndList
  (if (findfile (cdr n))
    ()
    (progn 
      (princ "\nMissing XREF: ")
      (princ (car n))
;;      (princ n)
    ) ; end progn
  ) ; end if
) ; end foreach

  (setq MyPath (cdr (nth 0 EndList)) )
  (setq MyFileType (xreftype (cdr (nth 0 EndList)) ))
  (setq MyFile (strcat (car (nth 0 EndList)) MyFileType) )
  (setq NewPath (strcat (getvar "dwgprefix") (vl-string-trim ".\\\\" MyPath ) ))

  (if (findfile NewPath) ; find file : if file exists
    (progn
      (setq MyPath (vl-string-right-trim MyFile MyPath ))   ; take off file from file path
      (setq NewPath (vl-string-right-trim MyFile NewPath )) ; take off file from file path
    ) ; end progn
    (progn
    ) ; end progn
  ) ; end if
)

 

 

Not sure if this is something you can use?

https://www.autodesk.com/support/technical/article/caas/sfdcarticles/sfdcarticles/Determining-whether-a-drawing-is-referenced-as-an-xref-in-other-drawings.html