Linking and maintaining Reactors

I am new to reactors. I want to write a routine that will keep track of object once they are created and when they are modified. I have looked at examples, and somewhat understand how it is done. What I don't know how to do is have AutoCAD still recognize those objects (entities) once I exit AutoCAD and re-enter AutoCAD. How can I have it remember which objects in the drawing are linked to my reactors and continue tracking them? Can anyone help? even if it is pointing me to a good book on the subject.

Thank you

 

Hi mloreto

Transient Reactors (the default mode) are lost when a drawing closes.
Persistent reactors are saved with the drawing.
Note:
If you open a drawing containing persistent reactors and the associated
functions are not available, AutoCAD shows an error message.

In case of transient reactors, write the notification data in a Xdata or
Xrecord (dictionary) structure and add the reactor to the associated object
when a drawing opens.

- AutoCAD's help
- The Garden Path tutorial
- This ng
- Dave Stein's Visual LISP Developers Bible (see customer-files ng)
- ???

Cheers

 

You can use (vlr-pers robj) to make it persistant.
You'll need to load all your reactor functions each time you open the drawing though.
Also to remove the persistance, use (vlr-pers-release robj).
You'll also need to set the reactor data to nil (vlr-data-set robj nil) in order to remove the error
message that occurs when you reopen the the drawing again.
This is the routine I use to destroy the reactor when the object is erased.

;; -----------------------------------------------------------------------------------------------

(defun reactor_obj_erased (nobj robj plist)

(vlr-owner-remove robj nobj)
(vlr-remove robj) ; disable the reactor
(vlr-pers-release robj) ; remove persistance so that the reactor
; won't be here next time
(vlr-data-set robj nil) ; eliminates the "; warning:erased VLA-object
; restored to NIL" message when reopening...
(prompt "\nReactor removed...\n")
)
;; -----------------------------------------------------------------------------------------------


Several people here think the AutoCAD reactors are more hassle than they're worth, and reccommend
using a custom dictionary to "roll their own", but I haven't had any problems with them (esp since
Luis E. helped me figure out what was going on with them. Thanks Luis!)

 

Thank you Jurg.

I will look into these Persistent reactors.

Thanks,

Miguel

 

Thank you Allen,

I will look into this. All of this is very helpful


Thanks,

Miguel