This will need to be approached over COM interop in FPC
Can I this resolved?
I don't know if it is always possible (if there are .NET assemblies that can't be interfaced from Delphi/FPC easily).
If I undestand right? With COM interop....Do you have some documentation of this please? I found nothing.
Strange. When I put "com interop" in google, I get pages of stuff.
It is the way all .NET code interfaces with native win32 or win64 code. Delphi and FPC just have some ways of make that easier (like the ability to define COM compatible interfaces)
Documentation is Microsoft for the general .NET->native case, and look for Delphi and COM for some more specific info.
I just needed to know enough to avoid .NET only software products, never done it myself.
Or it could be possible convert .net dll to normal .dll?
Not that I know. At best you can generate some DLL that talks to .NET which then (should) loads the .NET assembly DLL internally
I understand right that normal .dll is win32/com .dll library?
Normal dll is win32. Some dlls might also contain COM. .NET is COM based internally, but piles extra layers on top.
As said the subject to look for is .NET<->COM interop to get the fundamental concepts, and then general Delphi (and thus FPC/Lazarus) ways to connect to COM.
I never done it myself, so can only give you general pointers like
https://stackoverflow.com/questions/16785357/how-to-call-net-from-delphi (found with Delphi call .net)