NPOI读写Excel sheet操作

QueryInfo dataInfo = new QueryInfo();
            dataInfo.CustomSQL = $@"
                            select t1.name name,t1.url url from sys_menu t1
                            start with t1.parent_id =
                            (
                              select t2.id from sys_menu t2 where t2.name =‘交易源数据‘

                            )
                            connect by t1.parent_id=t1.id
                  ";
            var descpsInfo = new QueryInfo();

            var dataTable = Dao.ExcuteDataSet(dataInfo).Tables[0];
            foreach (DataRow row in dataTable.Rows)
            {
                var china_name = row["name"]==null?"":row["name"].ToString();
                var en_name = Holworth.Utility.ListAndTableExtension.ConvertToTableColumnName
                    (row["url"].ToString().Split(‘/‘)[row["url"].ToString().Split(‘/‘).Length - 1].Replace("Manage.aspx", ""));
                descpsInfo.CustomSQL = string.Format(@"
                            select (select t.COMMENTS from all_tab_comments t where t.TABLE_NAME=‘{0}‘ AND t.OWNER=‘NETHRA‘) tComments,
                             tt.TABLE_NAME ,
                            tt.COLUMN_NAME ,
                             (select t2.COMMENTS cComments from all_col_comments t2 where t2.column_name=tt.column_name and t2.OWNER=‘NETHRA‘ AND T2.TABLE_NAME=‘{0}‘) cComments,
                            tt.DATA_TYPE,tt.DATA_LENGTH,tt.DATA_PRECISION from all_tab_columns tt where tt.OWNER=‘NETHRA‘ AND TT.TABLE_NAME=‘{0}‘
                ",en_name);

                //descpsInfo.CustomSQL=string.Format(descpsInfo.CustomSQL,en_name);
                var dic = Dao.ExcuteDataSet(descpsInfo).Tables[0].AsEnumerable().Select
               (
               x => new
               {
                   tableName = x["TABLE_NAME"]==null?"":x["TABLE_NAME"].ToString(),
                   tComments = x["tcomments"]==null?"":x["tcomments"].ToString(),
                   columnsName = x["COLUMN_NAME"]==null?"":x["COLUMN_NAME"].ToString(),
                   cComments = x["cComments"]==null?"":x["cComments"].ToString(),
                   dataType = x["DATA_TYPE"].ToString(),
                   columnDataLength = x["DATA_LENGTH"].ToString(),
                   columnDataPrecious = x["DATA_PRECISION"].ToString(),

               }

               ).ToList();

                //1.创建excel文件
                string file = @"C:\Users\admin\Desktop\本周纪要\3.xlsx";

                XSSFWorkbook workbook = null;
                if (!File.Exists(file))
                {
                    workbook = new XSSFWorkbook();
                }
                else
                {

                    workbook = new XSSFWorkbook(File.OpenRead(file));
                }

                // 新建一个Excel页签
                //1.1创建固定部分前两行

                var sheet = workbook.CreateSheet(china_name);

                IRow row1 = sheet.CreateRow(0); //创建sheet页的第0行（索引从0開始）
                int start = 2;
                //1.1.1表头
                row1.CreateCell(0, CellType.String).SetCellValue("中文表名");
                row1.CreateCell(1, CellType.String).SetCellValue(china_name);
                row1.CreateCell(2, CellType.String).SetCellValue("英文表名");
                row1.CreateCell(3, CellType.String).SetCellValue(en_name);
                row1.CreateCell(4, CellType.String).SetCellValue("主键");
                row1.CreateCell(5, CellType.String).SetCellValue("备注");  //1.1.2列头
                IRow row2 = sheet.CreateRow(1);
                row2.CreateCell(0, CellType.String).SetCellValue("英文名称");
                row2.CreateCell(1, CellType.String).SetCellValue("中文名称");
                row2.CreateCell(2, CellType.String).SetCellValue("数据类型");
                row2.CreateCell(3, CellType.String).SetCellValue("是否为空");
                row2.CreateCell(4, CellType.String).SetCellValue("");
                row2.CreateCell(5, CellType.String).SetCellValue("");  

                using (Stream stream =File.OpenWrite(file))
                {

                    foreach (var item in dic)
                    {
                        var columnName = item.columnsName;
                        var cComment = item.cComments;
                        var cDataType = item.dataType;
                        var cLength = item.columnDataLength;
                        var cPrecious = item.columnDataPrecious;
                        //是否为空需要人判断默认为空
                        IRow tmpRow = sheet.CreateRow(start++);
                        //上述信息写入excel文件
                        tmpRow.CreateCell(0, CellType.String).SetCellValue(columnName);
                        tmpRow.CreateCell(1, CellType.String).SetCellValue(cComment);
                        tmpRow.CreateCell(2, CellType.String).SetCellValue(cDataType);
                        tmpRow.CreateCell(3, CellType.String).SetCellValue("Y");
                        tmpRow.CreateCell(4, CellType.String).SetCellValue("");
                        tmpRow.CreateCell(5, CellType.String).SetCellValue(""); 

                    }
                    start = 2;
                    workbook.Write(stream); //将这个workbook文件写入到stream流中

                }

            }