public Monitor(UIElement element)
{
this.Element = element;
this.HwndSource = ScreenLocation.FindTopLevelHwndSource(element);
this.Element.LayoutUpdated += new EventHandler(this.OnLayoutUpdated);
PresentationSource.AddSourceChangedHandler((IInputElement)element, new SourceChangedEventHandler(this.OnPresentationSourceChanged));
}
private static IntPtr FindTopLevelWindow(IntPtr hWnd)
{
while (hWnd != IntPtr.Zero && ScreenLocation.IsChildWindow(hWnd))
{
hWnd = NativeMethods.GetParent(hWnd);
}
return(hWnd);
}
public static HwndSource FindTopLevelHwndSource(UIElement element)
{
HwndSource hwndSource = (HwndSource)PresentationSource.FromVisual((Visual)element);
if (hwndSource != null && ScreenLocation.IsChildWindow(hwndSource.Handle))
{
hwndSource = HwndSource.FromHwnd(ScreenLocation.FindTopLevelWindow(hwndSource.Handle));
}
return(hwndSource);
}
private void TryUpdateLocation()
{
if (this.HwndSource == null || !this.Element.IsArrangeValid)
{
return;
}
Point point = DpiHelper.DeviceToLogicalUnits(this.Element.PointToScreen(new Point(0.0, 0.0)));
ScreenLocation.SetLeft(this.Element, point.X);
ScreenLocation.SetTop(this.Element, point.Y);
ScreenLocation.SetRight(this.Element, point.X + this.Element.RenderSize.Width);
ScreenLocation.SetBottom(this.Element, point.Y + this.Element.RenderSize.Height);
}
private void OnPresentationSourceChanged(object sender, SourceChangedEventArgs args)
{
this.HwndSource = ScreenLocation.FindTopLevelHwndSource((UIElement)sender);
this.TryUpdateLocation();
}