How to conquer entsel's defection?

[Ahankhah]

Hello friends,

 

as some of you know, entsel is a good function to select single objects, but it has a severe flaw in distinguishing between "pressing enter" and "selecting nothing":(.

 

Has Anyone a suggestion to conquer this defection:oops:?

[BlackBox]

I'm not sure I understand your question... What behavior are you trying to invoke?

[Ahankhah]

Here is the code:

(defun C:Length () (MT-TotalLength))

(defun MT-TotalLength (/ *error* ans layname cont len)
   (MT-Start)
   (initget "Name eXit _Name eXit")
   (setq ans nil)
   (setq ans
            (entsel
                "\nSelect an object on the layer to proceed [Name/eXit] <eXit>: "
            )
   )
   (cond
       ((member ans '(nil "eXit")) (exit))
       ((= "Name" ans)
        (setq cont T)
        (while cont
            (setq layname (getstring T "\nEnter layer name: "))
            (if (null (read layname))
                (progn (princ "\nNull name for layer not allowed, try again."))
                (progn (if (tblsearch "layer" layname)
                           (setq cont nil)
                           (princ (strcat "\nLayer \""
                                          layname
                                          "\" not exists, try again."
                                  )
                           )
                       )
                )
            )
        )
       )
       (T (setq layname (cdr (assoc 8 (entget (car ans))))))
   )
   (and (setq ss (ssget "_X"
                        (list (cons -4 "<OR")
                              (cons 0 "LINE")
                              (cons 0 "ARC")
                              (cons 0 "LWPOLYLINE")
                              (cons -4 "OR>")
                              (cons 8 layname)
                        )
                 )
        )
        (setq len (MT-Calc-Length ss))
   )
   (setq msg
            (strcat
                "Total length of objects (Lines, Arcs, Polylines) in layer:   \""
                layname
                "\"\n\nequals to:   "
                (rtos len)
            )
   )
   (princ msg)
   (alert msg)
   (MT-End)
)

(defun MT-Calc-Length (ss / sslist len)
   (setq sslist (MT-Conv-SS-To-List ss))
   (setq len 0)
   (foreach obj sslist (setq len (+ len (MT-Get-Obj-Length obj))))
)

(defun MT-Conv-SS-To-List (ss / entlist index)
   (setq entlist nil)
   (if (= 'PICKSET (type ss))
       (progn (setq index -1)
              (repeat (sslength ss)
                  (setq
                      entlist (append (list (ssname ss (setq index (1+ index))))
                                      entlist
                              )
                  )
              )
       )
   )
   (reverse entlist)
)

(defun MT-Error (msg)
   (or (member (read msg) '(nil *BREAK *CANCEL*)); *EXIT* isn't an error condition
       (princ (strcat "\n** Error: " msg " **"))
   )
   (setvar 'Cmdecho 1)
   (princ)
)

(defun MT-Start () (setq *error* MT-Error) (setvar 'Cmdecho 0))

(defun MT-End () (MT-Error ""))

(defun MT-Exit () (exit))

 

As you can check, there is no difference between pressing Enter and clicking mouse botton in an empty area in work space.

This is the above mentioned restriction.

[alanjt]

Use the errno variable with while

[Lee Mac]

As Alan states - can can use the ERRNO System Variable...

 

See here for an example.

[Ahankhah]

alanjt & Lee Mac, thank you very much.

I will use the instruction and the mentioned code.

[alanjt]

enjoy......