毫米转像素 高度

 /// <summary>
        /// 毫米转像素  高度
        /// </summary>
        /// <param name="length"></param>
        /// <param name="frmHandle">当前窗口/控件句柄</param>
        /// <returns></returns>
        public static float MillimetersToPixelsHeight(this float length, IntPtr frmHandle)
        {
            Graphics g = Graphics.FromHwnd(frmHandle);
            return length * (g.DpiY / 25.4f);
        }