How to find out from MFC application if the system is in the locked state (windows lock)

You can not find that put in a direct way, but 'WTSRegisterSessionNotification()'  (http://msdn.microsoft.com/en-us/library/aa383841(VS.85).aspx) allows  you to monitor when the workstation enters the 'locked' state. You'll get a message sent to the window you register the notification for that indicates 'WTS_SESSION_LOCK', then you know that it is locked.

Jkr,

Thanks for the link... this is perfect...

How do i Locate the WndProc window procedure and add a case statement to process WM_WTSSESSION_CHANGE messages.

Can anyone attach a snippet on how to access the WndProc window

Jkr,

Thanks for the snippet. But it does not get triggered (OnSessionChange) when i lock my computer (Windows+L button)
Here is my code when i added the calls to Mainfrm.cpp

//mainfrm.h
class CMainFrame : public CFrameWnd
{
afx_msg LRESULT OnSessionChange(WPARAM, LPARAM); 
..
}
 
//mainfrm.cpp
 
IMPLEMENT_DYNCREATE(CMainFrame, CFrameWnd)
 
BEGIN_MESSAGE_MAP(CMainFrame, CFrameWnd)
	//{{AFX_MSG_MAP(CMainFrame)
	ON_WM_CREATE()
	ON_WM_PAINT()
	ON_WM_SIZING()
...
 
     ON_MESSAGE( WM_WTSSESSION_CHANGE, OnSessionChange ) // necessarya entry
END_MESSAGE_MAP()
 
..
LRESULT CMainFrame::OnSessionChange(WPARAM wParam, LPARAM)
{
  if (WTS_SESSION_LOCK == wParam)
  {
    AfxMessageBox("test");
  }
 
  return 0;
}

Select allOpen in new window

Um, you cannot see the message box in your hanler since 'lock' actually meand switching to a different desktop - try 'MessageBeep()' instead.