Viewport Based Layerstates

[BHenry85]

I am trying to create some layerstates that will check to see if layers exist prior to making the changes to the properties on a list of layers, but when you use the VPLAYER command, the layer has to exist or it will throw an error and break the routine. I found a suggestion here, but I find that it doesn't work either.

 

https://www.cadtutor.net/forum/topic/29171-check-to-so-if-a-layers-exists-if-so-do-something-if-not-skip/

 

Can someone review the attached file that I have provided and maybe provide some insight on where I went wrong? I thank everyone in advance for any assistance on this matter. 

Viewport Layerstates.lsp

[BIGAL]

You have almost answered your own question you can search the layer table for does it exist. So do a check and then do your IFS. BIt shorter than looking at every layer.

 

So some suggestions.

 

(if (tblsearch "Layer" layername)
(princ "yes")
(princ "No")
)

 

Re IF's and but, it is better to do a (cond rather than individual IF's.

 

(cond
((LayerWCMatch "FP1 - Appliances")	(command "VPLAYER" "_thaw" "FP1 - Appliances"	"C" ""))
((LayerWCMatch "FP1 - Attic Access")(command "VPLAYER" "_thaw" "FP1 - Attic Access"	"C" ""))
.............
)

Maybe

((tblsearch "Layer" "FP1 - Appliances")	

 

I dont think you can use a wildcard in searching layer names

 

(TBLSEARCH "LAYER" "TEST22|C-ROAD-INTS")
((0 . "LAYER") (2 . "test22|C-ROAD-INTS") (70 . 48) (62 . 5) (6 . "Continuous"))

(TBLSEARCH "LAYER" "*|C-ROAD-INTS")
nil 
Wildcard not accepted 

 

So it may be better to add the xref name to the layer name being looked for.

(tblsearch "Layer"  (strcat xrefname "|FP1 - Appliances"))

So would need to wrap the vplayer in a loop of Xref names.

 

I tested on 500+ layers and it crashed. Using Tblsearch was instant return for xref layer.

 

Just one last comment rather than having multiple If's or a cond can make a list of layer names and use a foreach.

 

(foreach lay layerlst
(setq nlayname (strcat xrefname "|" lay))
(if (tblsearch "Layer"  nlayname)
(command "VPLAYER" "_thaw" nlaynem	"C" "")
)
)

 

Edited April 10, 2023 by BIGAL

[BHenry85]

@BIGAL Thank you so much sir. I will work through revamping my code and running some tests tomorrow then follow up if I have any issues and/or additional questions.