vc设置窗口透明

::SetWindowLong(GetSafeHwnd(), GWL_EXSTYLE,
        ::GetWindowLongPtr(GetSafeHwnd(), GWL_EXSTYLE) | WS_EX_LAYERED);
    this->SetLayeredWindowAttributes(0, (255 * 70) / 100, LWA_ALPHA);