How to use :vlr-dwgfileopened reactor event in drawing load

Hello.

I have a lisp that activates a reactor callback for :vlr-dwgfileopened. It is in the on_doc_load.lsp file. The lisp kind of works. Activates the callback only when a drawing is already open and I call open another or a new drawing. If I open a dwg file when another drawing is not open it fails to call the callback. To make it interesting though, it will call the callback on any attached xrefs to that drawing. I think it is a timing problem but I don't know how to get around this. Here is the code:

;; This file should be saved as 'on_doc_load.lsp' (or 'acaddoc.lsp' for AutoCAD)

;; and placed in your BricsCAD/AutoCAD support file search path.
;; Ensure the Visual LISP COM library is loaded.

(vl-load-com)
;; --- Global Variable for the Reactor ---

;; This variable will store the reactor object.

;; It's set to nil initially and will hold the reactor if it's successfully attached.

(setq simpleDwgOpenReactor nil)
;; --- Callback Function for the Drawing Open Event ---

;; This function will be executed whenever a drawing is opened.

;; 'reactor-object' is the reactor that triggered the event.

;; 'event-info' is a list containing a string (path to template/file).

(defun SimpleDrawingOpenAlertCallback (reactor-object event-info / docName processedEventInfo)

;; --- CRITICAL FIX: Ensure COM library is loaded at callback execution ---

(vl-load-com)
;; For debugging:

(print "event-info (raw): ") (print event-info)
;; As established, event-info is consistently a list. Extract the first item.

(setq processedEventInfo (car event-info))
;; For debugging:

(princ (strcat "Hello yor event info is: " processedEventInfo))
(princ) ; Suppress nil return in the command line

)
;; --- Function to Attach the Drawing Open Reactor ---

;; This function ensures the reactor is attached only once per AutoCAD/BricsCAD session.

;; It prevents redundant reactor attachments if on_doc_load.lsp is loaded multiple times.

(defun AttachSimpleDwgOpenReactor ()

(vl-load-com) ; Ensure COM is loaded
;; Check if the reactor is NOT already attached in this session

(if (not simpleDwgOpenReactor)

(progn

;; Create and store the vlr-dwg-reactor

(setq simpleDwgOpenReactor

(vlr-dwg-reactor "MySimpleTestReactor" ; A unique name for this reactor

'(

(:vlr-dwgfileopened . SimpleDrawingOpenAlertCallback) ; Event-callback pair

)

)

)

(princ "\nSimple Drawing Open Reactor ATTACHED successfully.")

)

(princ "\nSimple Drawing Open Reactor is ALREADY active.")

)

(princ)

)
;; --- Initial Call to Attach the Reactor ---

;; This line ensures that when 'on_doc_load.lsp' is loaded (which happens

;; every time a drawing is opened), it attempts to attach the reactor.

;; The 'AttachSimpleDwgOpenReactor' function's internal check prevents

;; it from attaching more than once per BricsCAD/AutoCAD session.

(AttachSimpleDwgOpenReactor)
(princ "\n'on_doc_load.lsp' script loaded. Reactor setup complete.")

(princ)

Does anyone know what is going on and how to fix this.

This lisp's only function is to print the name of the callback event. It is just for me to figure out how to us the reactor. Eventually I will be using it to load data from dictionaries on drawing open but that is for later.