private void SetTopmostState(bool isTop) {
// Don’t apply state if it’s the same as incoming state
if (m_appliedTopMost.HasValue && m_appliedTopMost == isTop) {
return;
}
if (Child == null)
return;
var hwndSource = (PresentationSource.FromVisual(Child)) as HwndSource;
if (hwndSource == null)
return;
var hwnd = hwndSource.Handle;
RECT rect;
if (!GetWindowRect(hwnd, out rect))
return;
Debug.WriteLine("setting z-order " + isTop);
if (isTop) {
SetWindowPos(hwnd, HWND_TOPMOST, rect.Left, rect.Top, (int)Width, (int)Height, TOPMOST_FLAGS);
}
else {
// Z-Order would only get refreshed/reflected if clicking the
// the titlebar (as opposed to other parts of the external
// window) unless I first set the popup to HWND_BOTTOM
// then HWND_TOP before HWND_NOTOPMOST
SetWindowPos(hwnd, HWND_BOTTOM, rect.Left, rect.Top, (int)Width, (int)Height, TOPMOST_FLAGS);
SetWindowPos(hwnd, HWND_TOP, rect.Left, rect.Top, (int)Width, (int)Height, TOPMOST_FLAGS);
SetWindowPos(hwnd, HWND_NOTOPMOST, rect.Left, rect.Top, (int)Width, (int)Height, TOPMOST_FLAGS);
}
m_appliedTopMost = isTop;
}