C#判断ListBox是否显示了水平滚动条/横向滚动条

参看：

Windows消息定义网址：http://wenku.baidu.com/link?url=9fesYjbLSDx9_TsLgSZSVoR7ELal-60x2p-lua_iPR44Xfekz0N5p2MxoAbJHzrXWH_FgDeyKSczHDHfa-QDKPGsQy3BnE2wootlnPeXFtu

还有 http://bbs.****.net/topics/80015678

private static class NativeMethods
        {
            public const int GWL_STYLE = -;
            public const long WS_HSCROLL = 0x00100000;

            [DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Auto)]
            internal static extern uint GetWindowLong(IntPtr hwnd, int nIndex);

            internal static bool HasHorizontalScrollbar(Control control)
            {
                long i = (GetWindowLong(control.Handle, GWL_STYLE) & WS_HSCROLL);
                return i > ;
            }
        }

若有更好方法，欢迎留言推荐。