跨窗口测试?

使用纯WPF是不可能的,因为WPF不公开其窗口的Z顺序。事实上,WPF努力保持这样一种错觉,即windows从来不会掩盖彼此。

public Window FindWindowAt(Point screenPoint)  // WPF units (96dpi), not device units
{
  return (
    from win in SortWindowsTopToBottom(Application.Current.Windows.OfType<Window>())
    where new Rect(win.Left, win.Top, win.Width, win.Height).Contains(screenPoint)
    select win
  ).FirstOrDefault();
}

public static IEnumerable<Window> SortWindowsTopToBottom(IEnumerable<Window> unsorted) 
{ 
  var byHandle = unsorted.ToDictionary(win => 
    ((HwndSource)PresentationSource.FromVisual(win)).Handle); 

  for(IntPtr hWnd = GetTopWindow(IntPtr.Zero); hWnd!=IntPtr.Zero; hWnd = GetWindow(hWnd, GW_HWNDNEXT))
    if(byHandle.ContainsKey(hWnd)) 
      yield return byHandle[hWnd]; 
} 

const uint GW_HWNDNEXT = 2; 
[DllImport("User32")] static extern IntPtr GetTopWindow(IntPtr hWnd); 
[DllImport("User32")] static extern IntPtr GetWindow(IntPtr hWnd, uint wCmd); 

如果你的窗口可能是透明的,你也应该使用VisualTreeHelper.HitTest测试在FindWindowAt()的where子句中。