Can a windows service in c# run only for current user?

No, this is against the whole idea of the service. A Windows Service is an application which can work independently of the users. It works without any desktop, will continue to execute when all users log off, and, if it is configured for auto-start, it happens before any users log on.

At the same time, a Windows Server is related to some account. Its behavior (permissions granted to the application) depends on the user account attributed to the service installation. Usually, this is one of the "special" account (most typically "Network Service", "Local System" or "Local Service"), but it can also log as a regular interactive user, and, in that case, it should be given a password of the user. Using an account of some interactive user for a service logon in not a desirable practice.

And of course, a service can detect different system events, such as user login and log off, communicate with the current user through some interactive application, and the like. It would not be a typical or intended behavior; and I don't think this is related to your question. It is not clear why are you interested in such a weird thing. It is possible that you could get some useful practical advice if you explained your ultimate goals.

—SA