How to detect inactive user

Question

How to detect inactive (idle) user in Windows application? I'd like to shutdown application when there hasn't been any input (keyboard, mouse) from user for certain period of time.

Answer 1

To track a user's idle time you could hook keyboard and mouse activity. Note, however, that installing a system-wide message hook is a very invasive thing to do and should be avoided if possible, since it will require your hook DLL to be loaded into all processes.

Another solution is to use the GetLastInputInfo API function (if your application is running on Win2000 (and up) machines). GetLastInputInfo retrieves the time (in milliseconds) of the last input event (when the last detected user activity has been received, be it from keyboard or mouse).

Here's a simple example. The SecondsIdle function returns a number of second with no user activity (called in an OnTimer event of a TTimer component).

~~~~~~~~~~~~~~~~~~~~~~~~~ function SecondsIdle: DWord; var    liInfo: TLastInputInfo; begin    liInfo.cbSize := SizeOf(TLastInputInfo) ;    GetLastInputInfo(liInfo) ;    Result := (GetTickCount - liInfo.dwTime) DIV 1000; end;  procedure TForm1.Timer1Timer(Sender: TObject) ; begin    Caption := Format('System IDLE last %d seconds', [SecondsIdle]) ; end; 

http://delphi.about.com/od/adptips2004/a/bltip1104_4.htm

Answer 2

You might want to see the answer to this question: How to tell when Windows is inactive [1] it is basically same question the solution suggested is to use the GetLastInputInfo [2] API call.

This post explains some aspects as well: (The Code Project) How to check for user inactivity with and without platform invokes in C# [3]

[1] How to tell when Windows is inactive
[2] http://msdn.microsoft.com/en-us/library/ms646302%28VS.85%29.aspx
[3] http://www.codeproject.com/KB/cs/uim.aspx