How to call Lisp functions from .Net

[Anonymous]

I have a Lisp routine which gets the field code from attribute. I need to run this function when changing attribute field codes as this is not exposed in .Net API !. I can not use SendStringToExecute as it waits until the .Net program is finished. How do I go about that.
I tried acedCmd with DllImport but no success as it doesn't run AutoLisp routines.
Thanks,

[Anonymous]

Thank you for the help.

Using your code Autocad return this:

"Autodesk.AutoCAD.Runtime.Exception: eInvalidInput
в Autodesk.AutoCAD.Runtime.Interop.CheckAds(Int32 returnValue)"