CODEWITHSUNDEEP
c#
TamerM
TamerM

Reputation: 762

Capturing Windows Users Session Switch event for all Users?

I am making a Windows Desktop Application that will run only one instance per machine. Once it gets started I need to get notified anytime a user logs in even if it was a session unlock? The SystemEvents.SessionSwitch event captures only the session switch for the user that started the application while I need to capture the events for all users.

Upvotes: 1

Views: 2495

Answers (1)

Andre Hofmeister
Andre Hofmeister

Reputation: 3416

I think you have to use a Windows Service, which executes before a user logged in, into your system, to capture all events. After that notify your application about the changes. I use following approach.

  1. Catch the different events with an ServiceBase.OnSessionChange event handler.
  2. Get the associated user information from the SessionId in SessionChangeDescription struct, from the wtsapi32 and the WTSQuerySessionInformation method.

I added the basic parts of this implementation below.

public class CustomService : ServiceBase
    protected override void OnSessionChange(SessionChangeDescription desc)
    {
        switch (desc.Reason)
        {
            case SessionChangeReason.SessionLogon:
                var user = CustomService.UserInformation(desc.SessionId);
                CustomService.DoWhatEverYouWant(user);
            break;
        }   
    }

    private static User UserInformation(int sessionId)
    {
        IntPtr buffer;
        int length;

        var user = new User();

        if (NativeMethods.WTSQuerySessionInformation(IntPtr.Zero, sessionId, NativeMethods.WTS_INFO_CLASS.WTSUserName, out buffer, out length) && length > 1)
        {
            user.Name = Marshal.PtrToStringAnsi(buffer);

            NativeMethods.WTSFreeMemory(buffer);
            if (NativeMethods.WTSQuerySessionInformation(IntPtr.Zero, sessionId, NativeMethods.WTS_INFO_CLASS.WTSDomainName, out buffer, out length) && length > 1)
            {
                user.Domain = Marshal.PtrToStringAnsi(buffer);
                NativeMethods.WTSFreeMemory(buffer);
            }
        }

        if (user.Name.Length == 0)
        {
            return null;
        }

        return user;
    }
}

Upvotes: 3

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