public static void InitializeDeviceState(InputDevice inputDevice)
{
if (inputDevice == null || deviceStateDictionary.ContainsKey(inputDevice))
{
return;
}
Window window = inputDevice.ActiveSource.RootVisual as Window;
if (window == null)
{
return;
}
Point position = inputDevice.GetPosition(window);
DependencyObject directlyOver = inputDevice.GetDirectlyOver() as DependencyObject;
deviceStateDictionary.Add(inputDevice, new DragState(position, directlyOver));
}