Check if no user is currently logged on to Windows

Question

I'm writing a Windows Service application which listens for connections and performs certain tasks as instructed from a different application running on another computer on the network.

One of the tasks ensures no user is currently logged on, locks the workstation, delete some files, and then restarts the system. I considered using this solution to look through the list of running processes and check the user names, determining if no user is logged on by matchhing the user names against SYSTEM, NETWORK, etc. I realized I have PostgreSQL running which uses a user account named postgres so that wouldn't work. Checking if explorer.exe is running also wouldn't work because explorer sometmes crashes, or I sometimes end the process myself and restart it.

What would be a good way of determining that NO user is logged on to a workstation using C#?

Answer 1

Use WTSGetActiveConsoleSessionId() to determine whether anybody is logged on locally. Use WTSEnumerateSessions() to determine if there is any session at all (including remote terminal services sessions).

Answer 2

You tried to check whether explorer.exe is running or not. Why not go for the winlogon.exe process?

public bool isLoggedOn()
{
    Process[] pname = Process.GetProcessesByName("winlogon");
    if (pname.Length == 0)
        return false;
    else
        return true;
}

Answer 3

Another option, if you don't want to deal with the P/Invokes: use Cassia.

using Cassia;

public static bool IsSomeoneLoggedOn(string server)
{
    foreach (ITerminalServicesSession session in new TerminalServicesManager().GetSessions(server))
    {
        if (!string.IsNullOrEmpty(session.UserName))
        {
            return true;
        }
    }
    return false;
}