/// <include file='doc\ToolTip.uex' path='docs/doc[@for="ToolTip.GetWindowFromPoint"]/*' />
/// <devdoc>
/// Returns the HWND of the window that is at the specified point. This
/// handles special cases where one Control owns multiple HWNDs (i.e. ComboBox).
/// </devdoc>
/// <internalonly/>
private IntPtr GetWindowFromPoint(Point screenCoords, ref bool success)
{
Control baseVar = TopLevelControl;
IntPtr baseHwnd = IntPtr.Zero;
if (baseVar != null)
{
baseHwnd = baseVar.Handle;
}
IntPtr hwnd = IntPtr.Zero;
bool finalMatch = false;
while (!finalMatch)
{
Point pt = screenCoords;
if (baseVar != null)
{
pt = baseVar.PointToClientInternal(screenCoords);
}
IntPtr found = UnsafeNativeMethods.ChildWindowFromPointEx(new HandleRef(null, baseHwnd), pt.X, pt.Y, NativeMethods.CWP_SKIPINVISIBLE);
if (found == baseHwnd)
{
hwnd = found;
finalMatch = true;
}
else if (found == IntPtr.Zero)
{
finalMatch = true;
}
else
{
baseVar = Control.FromHandleInternal(found);
if (baseVar == null)
{
baseVar = Control.FromChildHandleInternal(found);
if (baseVar != null)
{
hwnd = baseVar.Handle;
}
finalMatch = true;
}
else
{
baseHwnd = baseVar.Handle;
}
}
}
if (hwnd != IntPtr.Zero)
{
Control ctl = Control.FromHandleInternal(hwnd);
if (ctl != null)
{
Control current = ctl;
while (current != null && current.Visible)
{
current = current.ParentInternal;
}
if (current != null)
{
hwnd = IntPtr.Zero;
}
success = true;
}
}
return(hwnd);
}