Hello ThunderMusic,

There is no fuction to detect whether the workstration locked. You can detect
it by checking if any window is visible

T> Hi,
T> I want to detect in my C# app (can use iterop) if the workstation is
T> locked.
T> I've seen on the web people saying it's impossible except by looking
T> if the
T> Screensaver process is running. There must be a clean way of doing it
T> because MSN detects it and can change your status based on this.
T> Does someone have a solution to this please?
T>
T> thanks
T>
T> ThunderMusic
T>
---
WBR,
Michael  Nemtsev :: blog: http://spaces.live.com/laflour

"At times one remains faithful to a cause only because its opponents do not
cease to be insipid." (c) Friedrich Nietzsche

When running on XP or higher you can register for session change
notifications by calling (through PInvoke) the TS API
"WTSRegisterSessionNotification", note that you need a Windows procedure to
capture the messages.

Here are the PInvoke declarations..

   [DllImport("wtsapi32.dll")]
   private static extern bool WTSRegisterSessionNotification(IntPtr hWnd,
int dwFlags);

   [DllImport("wtsapi32.dll")]
   private static extern bool WTSUnRegisterSessionNotification(IntPtr
hWnd);

and here how to register...

private const int NotifyForThisSession = 0; // This session only

WTSRegisterSessionNotification(this.Handle, NotifyForThisSession);

and here the messages you can check..

   private const int SessionChangeMessage = 0x02B1;
   private const int SessionLockParam = 0x7;
   private const int SessionUnlockParam = 0x8;

in your overriden WndProc.

   protected override void WndProc(ref Message m)
   {
       // check for session change notifications
       if(m.Msg == SessionChangeMessage)
       {
           if(m.WParam.ToInt32() == SessionLockParam)
               OnSessionLock(); // Do something when locked
           else if(m.WParam.ToInt32() == SessionUnlockParam)
               OnSessionUnlock(); // Do something when unlocked
       }

       base.WndProc(ref m);
       return;
   }

void OnSessionLock() {...}

..
void OnSessionUnlock() {...}

call "WTSUnRegisterSessionNotification" when you no longer need to be
notified...

Willy.