winform计算文本的所占的像素长度

        /// <summary>
        /// 计算文本的宽度
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public static int GetStringLength(string str, int AddLength = )
        {
            Font f = new Font("微软雅黑", 12F, System.Drawing.FontStyle.Regular, GraphicsUnit.Pixel);
            Size sif = TextRenderer.MeasureText(str, f, new Size(, ), TextFormatFlags.NoPadding);
            return sif.Width + AddLength;
            //MessageBox.Show((sif.Width / pdi).ToString());
        }