【备】C#四舍五入常识备份

　　   /// <summary>
        /// 真正的四舍五入
        /// </summary>
        /// <param name="inVal">需要进行四舍五入的数字</param>
        /// <param name="keep">保留小数位数</param>
        /// <returns>四舍五入后的数值</returns>
        public static string Round(string inVal, int keep)
        {
            if (decimal.Parse(inVal) > 0)
                return Math.Round(double.Parse(inVal) + 5 / Math.Pow(10, 3), keep, MidpointRounding.AwayFromZero).ToString();
            else
                return Math.Round(Convert.ToDouble(inVal), keep, MidpointRounding.AwayFromZero).ToString();
        }