#region 修约函数/// </summary>/// <param name="data_val">输入数值</param>/// <param name="len">保留几位小数</param>/// <returns></returns>public static decimal round_gbt8170(decimal data_val,int len){string num = data_val.ToString();string zs = num.Split('.')[0];//整数string xs = "";if(num.Split('.').Length>0)xs = num.Split('.')[1];//小数数if (len>= xs.Length)//小数位数<=需要保留几位小数{xs = xs.ToString().PadRight(len, '0');}else {string lxs = "";if(len>1)lxs = xs.Substring(0, len - 1);int ds = Convert.ToInt32(xs.Substring(len - 1, 1));//取保留小数位数的数字int ns =Convert.ToInt32(xs.Substring(len , 1));//取保留小数位数的下一位数字if (ns < 5)//舍去{xs = lxs + ds.ToString();}else if (ns >5)//进1{xs = lxs + (ds+1).ToString();}else if (ns ==5){string hs = "";//取保留小数位数的下一位数字的后面所有数字if (xs.Length - 1 > len)hs = xs.Substring(len + 1);if (hs != "" && Convert.ToInt32(hs) > 0)   //舍弃数字的最左一位数字是 5,且其后有非0数字时进一,即保留数字的末位数字加1xs = lxs + (ds + 1).ToString();else //拟舍弃数字的最左一位数字为5,且其后无数字或皆为0时,若所保留的末位数字为奇数(1,3，5,7,9)则进一，即保留数字的末位数字加1;若所保留的末位数字为偶数(0,2,4,6,8),则舍去。{if(ds%2==0) //所保留的末位数字为偶数(0, 2, 4, 6, 8),则舍去{xs = lxs + ds.ToString();}else  if (ds % 2 ==1) //,若所保留的末位数字为奇数(1,3，5,7,9)则进一，即保留数字的末位数字加1{xs = lxs + ds.ToString();xs = lxs + (ds + 1).ToString();}}}}decimal fh = data_val;if (len > 0)fh = Convert.ToDecimal(zs + "." + xs);elsefh = Convert.ToDecimal(zs);return fh;}#endregion