Step through block definition, Nil returned INSTEAD of last element.

When I try to step through a block definition, it returns nil INSTEAD of the
last element. Any ideas on why?

(defun dxf (code elist)
(cdr (assoc code elist))
)
;returns the block "header"
(setq cent2 (tblsearch "block" blockname))
;returns the line
(setq cent2(entget(entnext(if (dxf -2 cent2)(dxf -2 cent2)(dxf -1 cent2)))))
;returns the text
(setq cent2(entget(entnext(if (dxf -2 cent2)(dxf -2 cent2)(dxf -1 cent2)))))
;returns the FIRST block
(setq cent2(entget(entnext(if (dxf -2 cent2)(dxf -2 cent2)(dxf -1 cent2)))))

;returns nil--why not the SECOND block?
(setq cent2(entget(entnext(if (dxf -2 cent2)(dxf -2 cent2)(dxf -1 cent2)))))

 

RDI,
You looking for the 2nd blockname in the 'block' table, or the
second block in the drawing by that name.
If in .dwg, do a (setq ss (ssget "_X" (list (cons 0 "INSERT") (cons 2 blockname)))); where blockname = "header"
If in block' table, there is only (1) block by that name,
use (foreach (setq cent2 (tblsearch 'block'...
Bob

 

try this snip from a toolbox routine
(defun GetBlockParts(blockname)
;if you want to modify block, need tblobjname, not tblsearch
(setq gbp:List(entget(tblobjname "BLOCK" blockname)))
;get first subentity of block definition
(setq gbp:subent(cdr(assoc -2 gbp:List)))
(while
gbp:subent
(print (cdr(assoc 0(entget gbp:subent))))
(setq gbp:subent(entnext gbp:subent)))
(princ)
)
(defun test2()
(setq blkname"YourBlockName")
(GetBlockParts blkname)
)

 

here's with a bit of cleanup and error checking
(defun PrintBlockParts(blockname / gbp:MasterList gbp:subent)
;if you want to modify block, need tblobjname, not tblsearch
(setq blkent (tblobjname "BLOCK" blockname))
(if blkent
(progn
(setq gbp:MasterList(entget blkent))
;get first subentity of block definition
(setq gbp:subent(CDR(ASSOC -2 gbp:MasterList)))
(princ(strcat "\nBlock " blockname " contains the following entity
types"))
(while
gbp:subent
(print (cdr(assoc 0(entget gbp:subent))))
(setq gbp:subent(entnext gbp:subent)))
);progn
(princ(strcat "No block found: " blockname))
);if
(princ)
)
(defun test()
(setq blkname"YourBlockName")
(PrintBlockParts blkname)
)

 

Thanks Mark! That worked great!

Why does tlbojname work better than tblsearch? From what I've seen, they
both return similar info.

The tblobjname returns the EntName which you then use entget to get the
entity list. While tblsearch returns the entity list.

 

why? I don't know...it's just that the help tells you that if you want to
modify an entity, you must use the list derived from tblobjname, instead of
the list from tblsearch. They look similar but if it's in the help it cant'
be wrong <g>! right? ~
So if you just need info, tblsearch is fine, if you need to modify info,
tblobjname is the key.