C#给DataTable添加序号、C#给DataTable添加合计、小计

 /// <summary>
        /// 给DataTable添加序号
        /// </summary>
        /// <param name="dt"></param>
        /// <param name="colXuHao"></param>
        public static void dbDataTableAddXuHao(DataTable dt,string colXuHao) {
            for (int i = 0; i < dt.Rows.Count; i++) {
                dt.Rows[i][colXuHao] = i + 1;
            }
        }
         /// <summary>
        /// 在DataTable末尾添加合计行，后两参数设置需要合计的行的范围,DataTableSumMultiCol(dt,1,2,5) //合计第3、4、5、6列
        /// </summary>
        /// <param name="dt"></param>
        /// <param name="nColHeJi">需要显示‘合计’字段的列</param>
        /// <param name="nMinColHeJi">起始合计的列</param>
        /// <param name="nMaxColHeJi">结束合计的列，-1表示全部</param>
        public static DataRow dbDataTableSumRowsWithColRange(DataTable dt, int nColHeJi, int nMinColHeJi, int nMaxColHeJi) {
            if (nMaxColHeJi == -1) nMaxColHeJi = dt.Columns.Count-1;
            if (nMaxColHeJi < nMinColHeJi) custError("合计列时，结束列要比起始列大!");
            int[] ix = new int[nMaxColHeJi - nMinColHeJi + 1];
            for (int i = 0; i < ix.Length; i++) {
                ix[i] = i + nMinColHeJi;
            }
            return dbDataTableSumRowsWithColList(dt, nColHeJi, ix);
            //int[] i = nmaxcolhe
        }
        /// <summary>
        /// 在DataTable末尾添加合计行，最后一个参数设置需要合计的列，DataTableSumMultiCol(dt,1,{2,6,8}) //合计第3、7、9列
        /// </summary>
        /// <param name="dt"></param>
        /// <param name="nColHeJi">需要显示‘合计’字段的列</param>
        /// <param name="colsHeJi">需要合计的列</param>
        public static DataRow dbDataTableSumRowsWithColList(DataTable dt, int nColHeJi, int[] colsHeJi) {
            DataRow dr = dt.NewRow();
            dr[nColHeJi] = "合计";
            dt.Rows.Add(dr);
            //初始化合计数组
            decimal[] arrDec = new decimal[colsHeJi.Length];
            for (int i = 0; i < colsHeJi.Length; i++) {
                arrDec[i] = decimal.Zero;
            }
            //合计
            for (int i = 0; i < dt.Rows.Count - 1; i++) {
                for(int j=0;j<colsHeJi.Length;j++){
                    int c = colsHeJi[j];
                    if (Convert.IsDBNull(dt.Rows[i][c])) continue;
                    arrDec[j] += Tools.toDec(dt.Rows[i][c] + "");
                }
            }
            //赋值
            for (int i = 0; i < colsHeJi.Length; i++) {
                int c = colsHeJi[i];
                if (arrDec[i] == decimal.Zero) dr[c] = DBNull.Value;
                else dr[c] = arrDec[i];
            }
            return dr;
        }
        /// <summary>
        /// 在DataTable末尾添加合计行，最后一个参数设置需要合计的列，Tools.dbDataTableSumRowsWithColList(dt,"车号",new string[]{"个人产值","节油（元）","超油（元）"});
        /// </summary>
        /// <param name="dt"></param>
        /// <param name="nColHeJi">需要显示‘合计’字段的列</param>
        /// <param name="colsHeJi">需要合计的列</param>
        public static DataRow dbDataTableSumRowsWithColList(DataTable dt, string sColHeJi, string[] colsHeJi) {
            DataRow dr = dt.NewRow();
            dr[sColHeJi] = "合计";
            dt.Rows.Add(dr);
            //初始化合计数组
            decimal[] arrDec = new decimal[colsHeJi.Length];
            for (int i = 0; i < colsHeJi.Length; i++) {
                arrDec[i] = decimal.Zero;
            }
            //合计
            for (int i = 0; i < dt.Rows.Count - 1; i++) {
                for (int j = 0; j < colsHeJi.Length; j++) {
                    string cName = colsHeJi[j];
                    if (Convert.IsDBNull(dt.Rows[i][cName])) continue;
                    arrDec[j] += Tools.toDec(dt.Rows[i][cName] + "");
                }
            }
            //赋值
            for (int i = 0; i < colsHeJi.Length; i++) {
                string cName = colsHeJi[i];
                if (arrDec[i] == decimal.Zero) dr[cName] = DBNull.Value;
                else dr[cName] = arrDec[i];
            }
            return dr;
        }
        /// <summary>
        /// 分类小计，并有合计行，
        /// </summary>
        /// <param name="dt"></param>
        /// <param name="nColHeJi">需要显示‘合计’字段的列</param>
        /// <param name="colsHeJi">需要合计的列</param>
        public DataRow dbDataTableSubSumRowsWithColList(DataTable dt, string sColHeJi, string[] colsGroup, string[] colsHeJi) {
            DataRow dr = dt.NewRow();
            dr[sColHeJi] = "合计";
            dt.Rows.Add(dr);
            //初始化合计数组
            decimal[] arrDec = new decimal[colsHeJi.Length];
            for (int i = 0; i < colsHeJi.Length; i++) {
                arrDec[i] = decimal.Zero;
            }
            //合计
            for (int i = 0; i < dt.Rows.Count - 1; i++) {
                for (int j = 0; j < colsHeJi.Length; j++) {
                    string cName = colsHeJi[j];
                    if (Convert.IsDBNull(dt.Rows[i][cName])) continue;
                    arrDec[j] += Tools.toDec(dt.Rows[i][cName] + "");
                }
            }
            for (int i = 0; i < colsHeJi.Length; i++) {
                string cName = colsHeJi[i];
                if (arrDec[i] == decimal.Zero) dr[cName] = DBNull.Value;
                else dr[cName] = arrDec[i];
            }
            if (dt.Rows.Count <= 1) return dr;
            //小计
            string sRate = "";
            int currSubSumCol = dt.Rows.Count - 2;
            ArrayList ar = new ArrayList();
            for (int i = dt.Rows.Count - 2; i >= 0; i--) {
                string currRate = dt.Rows[i]["税率（%）"] + "";
                if (sRate != currRate) {
                    if (i != dt.Rows.Count - 2) {
                        dr = dt.NewRow();
                        dr[sColHeJi] = "小计";
                        for (int j = 0; j < colsHeJi.Length; j++) {
                            string cName = colsHeJi[j];
                            if (arrDec[j] == decimal.Zero) dr[cName] = DBNull.Value;
                            else dr[cName] = arrDec[j];
                        }
                        dt.Rows.InsertAt(dr, currSubSumCol + 1);
                    }
                    currSubSumCol = i;
                    sRate = currRate;
                    for (int j = 0; j < colsHeJi.Length; j++) { //归零
                        arrDec[j] = decimal.Zero;
                    }
                }
                for (int j = 0; j < colsHeJi.Length; j++) {
                    string cName = colsHeJi[j];
                    if (Convert.IsDBNull(dt.Rows[i][cName])) continue;
                    arrDec[j] += Tools.toDec(dt.Rows[i][cName] + "");
                }
                if (i == 0) {
                    dr = dt.NewRow();
                    dr[sColHeJi] = "小计";
                    for (int j = 0; j < colsHeJi.Length; j++) {
                        string cName = colsHeJi[j];
                        if (arrDec[j] == decimal.Zero) dr[cName] = DBNull.Value;
                        else dr[cName] = arrDec[j];
                    }
                    dt.Rows.InsertAt(dr, currSubSumCol + 1);
                }
            }

            return dr;
        }