Topic: Help Using ENTNEXT to Update Block Attribute

[tcdan]

OK - so I didn't search this time to see if this question has been covered.

1. insert block
2. (setq en (entget (entlast)))
3. use ENTNEXT to cycle through attributes which I thought followed the main entity: (setq en (entget (entnext en)))

But when I try to use ENTNEXT, I get an error followed by the contents of the elist previously returned by entget:

Code: [Select]

; error: bad argument type: lentityp ((-1 . <Entity name: 7ecbe9e0>) (0 .
"INSERT") (330 . <Entity name: 7ef8bcb8>) (5 . "24214") (100 . "AcDbEntity")
(67 . 0) (410 . "Model") (8 . "EASMENTS") (6 . "Continuous") (100 .
"AcDbBlockReference") (66 . 1) (2 . "NORTHA") (10 6204.67 24007.3 0.0) (41 .
25.0) (42 . 25.0) (43 . 25.0) (50 . 0.0) (70 . 0) (71 . 0) (44 . 0.0) (45 .
0.0) (210 0.0 0.0 1.0))

   

[Jeff_M]

You must supply the ENAME for entnext:

Code: [Select]


(setq ent (entlast))
(setq entlist (entget ent))
(setq ent (entnext ent))
(setq entlist (entget ent))
(setq ent (entnext ent))
(setq entlist (entget ent))
;...etc. usually wrapped in a (while) loop


[tcdan]

Oh yeah, that makes sense.

I don't really understand the way entget uses ENAME's and what an ename really is and why you then you have to convert them to use them with VLA- functions and all that. . .

I'm guessing the ENAME is the unique identifier of the object in ACAD's database - kind of like a pointer - that is saved in the drawing and accessible from session to session of CAD.

[Jeff_M]

I'm guessing the ENAME is the unique identifier of the object in ACAD's database - kind of like a pointer - that is saved in the drawing and accessible from session to session of CAD.

The pointer part is correct, however the ename value changes from session to session. The only thing that stays the same is the entity's handle. The ename and vla-objectid are both recreated, AFAIK, every time the drawing is opened. (Although I have never run tests to verify this, I'm just repeating what I've read)

BTW, you CAN use (entnext) with the list returned by (entget)....you just need to do the entnext on the ename......

Code: [Select]

(setq ent (entnext (cdr (assoc -1 ent)))) should do it.

[MP]

ObjectID's do change session to session.

[tcdan]

BTW, you CAN use (entnext) with the list returned by (entget)....you just need to do the entnext on the ename......

Code: [Select]


(setq ent (entnext (cdr (assoc -1 ent))))
should do it.

That's pretty nifty. . . yeah - I like that.  Thanks jeff!

[tcdan]

Whoa man - nice emoticon.  Makes you look like a know it all

Did you insert that or attach it as an image or what
(or is it a secret)?

[tcdan]

http://www.theswamp.org/screens/mp/nodding.gif
Oh I see

[tcdan]

The only thing that stays the same is the entity's handle.

Could you clarify what that is?

[MP]

The handle is a guarenteed unique, sequentially assigned hexidecimal number.

PS: Not a know it all, just a knurd havin' fun.

[tcdan]

I can definitely appreciate that

[Jeff_M]

And to further clarify the handle, it is stored as DXF code 5. So every time you (entget) an object you can extract it's handle from (assoc 5 ent) and be certain that it is the same from session to session. It even gets saved when exporting to a DXF file.

[daron]

Of course, it gets changed if you happen to wblock it out.