Field with custom properties

[Kowal]

I created a custom peopertis. Name custim propertis: Test

I'm trying to put it in an existing text.
Why is this code not working?

(vla-put-TextString (vlax-ename->vla-object (car (entsel))) "%<\AcVar CustomDP.Test>%")

The code inserts text but the result is ####

[Tharwat]

You need to add another backslash like this "%<\\AcVar ......"

Can you upload your sample drawing to check it out if the above mod did not fully work?

[Kowal]

Thanks Tharwat!

Now the code works.

I'm just wondering why there is no additional \ in the expression in the field edit then.

[Tharwat]

You're welcome.

That's how autodesk built fields codes so we need to live with it.  

[Lee Mac]

10 hours ago, Kowal said:

I'm just wondering why there is no additional \ in the expression in the field edit then.

 

The backslash character in AutoLISP is an escape character, used to give the characters which follow it an alternatively meaning - for example, \n represents a newline, \t represents a tab character, \" represents a literal double quote (as opposed to a string delimiter). As such, if you want to represent a literal backslash in a string, this must be preceded by another backslash to mark it as a literal as opposed to the start of another escape character sequence (i.e. the first backslash is an escape character which gives the second backslash an alternative meaning, marking it as a literal character).

 

The reason that you only see one backslash everywhere else in the GUI is because the backslash is only an escape character in AutoLISP (and other programming languages).