Get windows username in c# windows service in 64-bit Windows 7?

Question

How to get the current logged in username from C# Windows service in Windows 7 64-bit system.

I'm using the following code which works fine in 32-bit Windows:

ManagementObjectSearcher searcher = 
       new ManagementObjectSearcher("SELECT UserName from Win32_ComputerSystem");

ManagementObjectCollection collection = searcher.Get();

string username = 
       (string)collection.Cast<ManagementBaseObject>().First()["UserName"];

But not run on 64 bit. please suggest

Thanks

Answer 1

A simple solution is to use Environment.UserName that normally contains the logged-on username.

There is cases where the service is running, no user logged-on and Environment.UserName is null or in cases where the env. variable was removed for some odd reason. You can make this variable required for that cases.

System.Security.Principal.WindowsIdentity.GetCurrent() may be null in more scenarios than Environment.UserName so be aware to not call System.Security.Principal.WindowsIdentity.GetCurrent().Name before checking that System.Security.Principal.WindowsIdentity.GetCurrent() really exists.

In case you want to figure out the current logged-on terminal services sessions you can make use of the following class:

public class TerminalServices {
    [DllImport("wtsapi32.dll", SetLastError = true)] 
    static extern IntPtr WTSOpenServer([MarshalAs(UnmanagedType.LPStr)] String pServerName);

    [DllImport("wtsapi32.dll")] 
    static extern void WTSCloseServer(IntPtr hServer);

    [DllImport("wtsapi32.dll", SetLastError=true)] 
    static extern Int32 WTSEnumerateSessions(IntPtr hServer, [MarshalAs(UnmanagedType.U4)] Int32 Reserved, [MarshalAs(UnmanagedType.U4)] Int32 Version, ref IntPtr ppSessionInfo, [MarshalAs(UnmanagedType.U4)] ref Int32 pCount);

    [DllImport("wtsapi32.dll")]
    static extern void WTSFreeMemory(IntPtr pMemory);

    [StructLayout(LayoutKind.Sequential)] 
    private struct WTS_SESSION_INFO {
        public Int32 SessionID;

        [MarshalAs(UnmanagedType.LPStr)] 
        public String pWinStationName;

        public WTS_CONNECTSTATE_CLASS State;
    }

    public enum WTS_CONNECTSTATE_CLASS {
        WTSActive,
        WTSConnected,
        WTSConnectQuery,
        WTSShadow,
        WTSDisconnected,
        WTSIdle,
        WTSListen,
        WTSReset,
        WTSDown,
        WTSInit
    } 

    public static IntPtr OpenServer(String Name) {
        IntPtr server = WTSOpenServer(Name);
        return server;
    }

    public static void CloseServer(IntPtr ServerHandle) {
        WTSCloseServer(ServerHandle);
    }

    public static List<Session> ListSessions(String ServerName) {
        var ret = new List<Session>();
        var server = OpenServer(ServerName);

        try {
            IntPtr ppSessionInfo = IntPtr.Zero;
            Int32 count = 0;
            Int32 retval = WTSEnumerateSessions(server, 0, 1, ref ppSessionInfo, ref count);
            Int32 dataSize = Marshal.SizeOf(typeof(WTS_SESSION_INFO));
            Int64 current = (int) ppSessionInfo;

            if (retval != 0) {
                for (int i=0; i<count; i++) {
                    WTS_SESSION_INFO si = (WTS_SESSION_INFO) Marshal.PtrToStructure((System.IntPtr) current, typeof(WTS_SESSION_INFO));
                    current += dataSize;

                    ret.Add(new Session { Id = si.SessionID, State = si.State.ToString(), Type = si.pWinStationName });
                }

                WTSFreeMemory(ppSessionInfo);
            }
        } finally {
            CloseServer(server);
        }

        return ret;
    }
}

public class Session {
    public int Id {
        get;
        set;
    }

    public string State {
        get;
        set;
    }

    public string Type {
        get;
        set;
    }
}

TerminalServices.ListSessions will tell you how many users and what users are logged on into that terminal.

Answer 2

Use this to get current logged on user. Mark it as answer if it works.

System.Security.Principal.WindowsIdentity.GetCurrent().Name;