I'm trying to read custom properties from the components in an assembly when that assembly is not Resolved (Lightweight or Large Design). I found this question in the forums that has come to the same conclusion that I have which is the components need to be resolved or the code needs to do an IO file read with document manager:

I guess my additional question that I want to raise for discussion is, why does the bill of materials have access to these custom properties for the components when an assembly is in lightweight mode but the API doesn't? Is the BOM table using document manger as well or is there some SolidWorks functionality that isn't exposed through the API?

If anyone has any additional insight on this, it would be appreciated.