TimeSpan getIdleTime()
{
var idleTime = new LASTINPUTINFO { cbSize = LASTINPUTINFO.SizeOf };
GetLastInputInfo(ref idleTime);
var currentTicks = GetTickCount();
long deltaTicks;
if (idleTime.dwTime > currentTicks) {
deltaTicks = (((long)currentTicks + UInt32.MaxValue) - idleTime.dwTime);
} else {
deltaTicks = currentTicks - idleTime.dwTime;
}
return new TimeSpan(deltaTicks);
}
static extern bool GetLastInputInfo(ref LASTINPUTINFO plii);