how to identify a name of user copy, delete or change a file in windows server

  c++, filesystemwatcher, server, windows

in my project i used filesystemwacher and this last work fine using service windows and task quene with out problem.
now i need to detecte name of user change files in the directory watched by my service, this help me to send a notification to other user to copy the last files modified in the local folder.
for this i have to create a new service to install it in the server but i need to know the name of user in this service where i use filesystemwatcher.
any way to get the name of user please???
i use c# for programming, sqlserver express to send notification and windows server 2016 with activedirectory controlled by domain.

Source: Windows Questions