/// <summary>
        /// 根据给定的X/Y轴坐标值,返回正切值
        /// </summary>
        /// <param name="cell"></param>
        /// <param name="x_row"></param>
        /// <param name="x_col"></param>
        /// <param name="y_row"></param>
        /// <param name="y_col"></param>
        public static void Atan2(this ICell cell, int x_row, int x_col, int y_row, int y_col)
        {
            string x = string.Concat(ExcelExtend.ColumnIndexToName(x_col), (x_row + 1));
            string y = string.Concat(ExcelExtend.ColumnIndexToName(y_col), (y_row + 1));

            cell.CellFormula = string.Concat("ATAN2(", x, ",", y, ")");
        }
        /// <summary>
        /// 按一年360天,计算两个(单元格)时间差时间
        /// </summary>
        /// <param name="cell"></param>
        /// <param name="beginRow"></param>
        /// <param name="beginCol"></param>
        /// <param name="endRow"></param>
        /// <param name="endCol"></param>
        public static void Days360(this ICell cell, int beginRow, int beginCol, int endRow, int endCol)
        {
            string begin = string.Concat(ExcelExtend.ColumnIndexToName(beginCol), (beginRow + 1));
            string end   = string.Concat(ExcelExtend.ColumnIndexToName(endCol), (endRow + 1));

            cell.CellFormula = string.Concat("DAYS360(", begin, ",", end);
        }
        /// <summary>
        /// 平均值
        /// </summary>
        /// <param name="cell"></param>
        /// <param name="beginRow"></param>
        /// <param name="beginCol"></param>
        /// <param name="endRow"></param>
        /// <param name="endCol"></param>
        public static void Average(this ICell cell, int beginRow, int beginCol, int endRow, int endCol)
        {
            string begin = string.Concat(ExcelExtend.ColumnIndexToName(beginCol), beginRow + 1);
            string end   = string.Concat(ExcelExtend.ColumnIndexToName(endCol), endRow + 1);

            cell.CellFormula = string.Concat("COUNT(", begin, ":", end, ")");
        }
        /// <summary>
        /// 标准差
        /// </summary>
        /// <param name="cell"></param>
        /// <param name="beginRow"></param>
        /// <param name="beginCol"></param>
        /// <param name="endRow"></param>
        /// <param name="endCol"></param>
        public static void Stdev(this ICell cell, int beginRow, int beginCol, int endRow, int endCol)
        {
            string begin = string.Concat(ExcelExtend.ColumnIndexToName(beginCol), (beginRow + 1));
            string end   = string.Concat(ExcelExtend.ColumnIndexToName(endCol), (endRow + 1));

            cell.CellFormula = string.Concat("STDEV(", begin, ":", end, ")");
        }
        /// <summary>
        /// 设置单独单元格 引用地址
        /// </summary>
        /// <param name="sheet"></param>
        /// <param name="rowIndex">行位置:从0开始</param>
        /// <param name="colIndex">列位置:从0开始</param>
        public static string RefersToFormula(this ISheet sheet, int rowIndex, int colIndex)
        {
            string refer = string.Empty;

            refer = string.Concat(sheet.SheetName, "!", "$", ExcelExtend.ColumnIndexToName(colIndex), "$", (rowIndex + 1));
            return(refer);
        }
        /// <summary>
        /// 取余数
        /// </summary>
        /// <param name="cell"></param>
        /// <param name="numRow"></param>
        /// <param name="numCol"></param>
        /// <param name="divRow"></param>
        /// <param name="divCol"></param>
        public static void Mod(this ICell cell, int numRow, int numCol, int divRow, int divCol)
        {
            string begin = string.Concat(ExcelExtend.ColumnIndexToName(numCol), (numRow + 1));
            string end   = string.Concat(ExcelExtend.ColumnIndexToName(divCol), (divRow + 1));

            cell.CellFormula = string.Concat("MOD(", begin, ",", end, ")");
        }
        /// <summary>
        /// 返回从开始时间 + N个工作日 - 节假日
        /// <para>注意:得到的是一个日期序列数</para>
        /// </summary>
        /// <param name="cell"></param>
        /// <param name="beginDateRow"></param>
        /// <param name="beginDateCol"></param>
        /// <param name="days"></param>
        /// <param name="beginHRow"></param>
        /// <param name="beginHCol"></param>
        /// <param name="endHRow"></param>
        /// <param name="enndHCol"></param>
        public static void WorkDay(this ICell cell, DateTime dateText, int days, int beginHRow, int beginHCol, int endHRow, int enndHCol)
        {
            string bh = string.Concat(ExcelExtend.ColumnIndexToName(beginHCol), (beginHRow + 1));
            string eh = string.Concat(ExcelExtend.ColumnIndexToName(enndHCol), (endHRow + 1));

            cell.CellFormula = string.Concat("WORKDAY(\"", dateText, "\",", days, ",", bh, ":", eh, ")");
        }
        /// <summary>
        /// 计算两个时间内工作日数
        /// </summary>
        /// <param name="cell"></param>
        /// <param name="beginRow"></param>
        /// <param name="beginCol"></param>
        /// <param name="endRow"></param>
        /// <param name="endCol"></param>
        public static void NetWorkDays(this ICell cell, int beginRow, int beginCol, int endRow, int endCol)
        {
            string begin = string.Concat(ExcelExtend.ColumnIndexToName(beginCol), (beginRow + 1));
            string end   = string.Concat(ExcelExtend.ColumnIndexToName(endCol), (endRow + 1));

            cell.CellFormula = string.Concat("NETWORKDAYS(", begin, ",", end, ")");
        }
        /// <summary>
        /// 获取区域单元格 引用地址
        /// </summary>
        /// <param name="sheet"></param>
        /// <param name="beginRow">开始行:从0开始</param>
        /// <param name="beginCol">开始列:从0开始</param>
        /// <param name="endRow">结束行:从0开始</param>
        /// <param name="endCol">结束列:从0开始</param>
        /// <returns></returns>
        public static string RefersToFormula(this ISheet sheet, int beginRow, int beginCol, int endRow, int endCol)
        {
            string refer = string.Empty;

            refer = string.Concat(sheet.SheetName, "!", "$", ExcelExtend.ColumnIndexToName(beginCol), "$", (beginRow + 1)) + ":" +
                    string.Concat("$", ExcelExtend.ColumnIndexToName(endCol), "$", (endRow + 1));
            return(refer);
        }
 /// <summary>
 /// 返回一数组所代表的矩阵行列式的值
 /// <para>数组:行数和列数必须相等</para>
 /// </summary>
 /// <param name="cell"></param>
 /// <param name="beginRow"></param>
 /// <param name="beginCol"></param>
 /// <param name="endRow"></param>
 /// <param name="endCol"></param>
 public static void Moeterm(this ICell cell, int beginRow, int beginCol, int endRow, int endCol)
 {
     if (endRow - beginRow == endCol - beginCol)
     {
         string begin = string.Concat(ExcelExtend.ColumnIndexToName(beginCol), (beginRow + 1));
         string end   = string.Concat(ExcelExtend.ColumnIndexToName(endCol), (endRow + 1));
         cell.CellFormula = string.Concat("MDETERM(", begin, ":", end, ")");
     }
 }
        /// <summary>
        /// 按一年360天,计算两个时间差时间
        /// 一个是单元数据,一个是固定日期
        /// </summary>
        /// <param name="cell"></param>
        /// <param name="dateText"></param>
        /// <param name="rowIndex"></param>
        /// <param name="colIndex"></param>
        /// <param name="flag">true:dateText作为结束日期,否则作为开始日期</param>
        public static void Days360(this ICell cell, DateTime dateText, int rowIndex, int colIndex, bool flag = true)
        {
            string begin = string.Concat(ExcelExtend.ColumnIndexToName(colIndex), (rowIndex + 1));

            if (flag)
            {
                cell.CellFormula = string.Concat("DAYS360(", begin, ",\"", dateText, "\")");
            }
            else
            {
                cell.CellFormula = string.Concat("DAYS360(\"", dateText, "\",", begin, ")");
            }
        }
        /// 根据给定底数返回数字的对数
        /// <para>底数默认10</para>
        public static void Log(this ICell cell, int rowIndex, int colIndex, int bs = 10)
        {
            string begin = string.Concat(ExcelExtend.ColumnIndexToName(colIndex), (rowIndex + 1));

            cell.CellFormula = string.Concat("LOG(", begin, ",", bs, ")");
        }
        /// <summary>
        /// 返回某数的乘幂
        /// </summary>
        /// <param name="cell"></param>
        /// <param name="numRow"></param>
        /// <param name="numCol"></param>
        /// <param name="pow"></param>
        public static void Power(this ICell cell, int numRow, int numCol, double pow)
        {
            string begin = string.Concat(ExcelExtend.ColumnIndexToName(numCol), (numRow + 1));

            cell.CellFormula = string.Concat("POWER(", begin, ",", pow, ")");
        }
        /// <summary>
        /// 返回某数的双阶乘
        /// </summary>
        /// <param name="cell"></param>
        /// <param name="rowIndex"></param>
        /// <param name="colIndex"></param>
        public static void FactDouble(this ICell cell, int rowIndex, int colIndex)
        {
            string begin = string.Concat(ExcelExtend.ColumnIndexToName(colIndex), (rowIndex + 1));

            cell.CellFormula = string.Concat("FACTDOUBLE(", begin, ")");
        }
        /// <summary>
        /// 返回e的n次方
        /// <para>常数e = 2.71828182845904</para>
        /// </summary>
        /// <param name="cell"></param>
        /// <param name="rowIndex"></param>
        /// <param name="colIndex"></param>
        public static void Exp(this ICell cell, int rowIndex, int colIndex)
        {
            string begin = string.Concat(ExcelExtend.ColumnIndexToName(colIndex), (rowIndex + 1));

            cell.CellFormula = string.Concat("EXP(", begin, ")");
        }
        /// <summary>
        /// 表示指定月数之前或之后的月份的最后一天
        /// <para>注意:得到的结果是一个日期序列</para>
        /// </summary>
        /// <param name="cell"></param>
        /// <param name="rowIndex"></param>
        /// <param name="colIndex"></param>
        /// <param name="months"></param>
        public static void EoMonth(this ICell cell, int rowIndex, int colIndex, int months)
        {
            string begin = string.Concat(ExcelExtend.ColumnIndexToName(colIndex), (rowIndex + 1));

            cell.CellFormula = string.Concat("EOMONTH(", begin, ",", months, ")");
        }
        /// <summary>
        /// 返回从开始时间 + N个工作日
        /// <para>注意:得到的是一个日期序列数</para>
        /// </summary>
        /// <param name="cell"></param>
        /// <param name="beginDateRow"></param>
        /// <param name="beginDateCol"></param>
        /// <param name="days"></param>
        public static void WorkDay(this ICell cell, int beginDateRow, int beginDateCol, int days)
        {
            string begin = string.Concat(ExcelExtend.ColumnIndexToName(beginDateCol), (beginDateRow + 1));

            cell.CellFormula = string.Concat("WEEKDAY(", begin, ",", days, ")");
        }