Read and Write Custom of a Block using autolisp

[22352065NTPYQ]

What is the autolisp syntax to read and write Custom of a block . It can be seen by selecting the object and executing command "PR (PROPERTIES)"  through UI.
I am using Autocad electrical 2025.

[Sea-Haven]

Electrical may have blocks that are proxy objects re custom objects, may need Electrical to get at those objects, similar problem with CIV3D. 

Can you post a sample dwg.

[komondormrex · Accepted solution]

@22352065NTPYQ 

normally the following expressions will work to get/set dynamic block properties

(getpropertyvalue (car (entsel)) "AcDbDynBlockPropertyDistance1")
(setpropertyvalue (car (entsel)) "AcDbDynBlockPropertyDistance1" 5)

[22352065NTPYQ]

Thanks a lot