阶段总结 2014-05-22

1：float保存2位小数：

    f1.ToString("F2")

2：datatable列求和：

dt.Compute("sum([企业数量])", "true")

同时：如果字段为中文，取值用[中文字段] 方式。

3：NPOI 导出EXCEL（需要手动导入NPOI文件）

单Sheet：

//单Sheet页导出
        public static Stream RenderDataTableToExcel(DataTable SourceTable)
        {
            HSSFWorkbook workbook = new HSSFWorkbook();
            MemoryStream ms = new MemoryStream();
            HSSFSheet sheet = (HSSFSheet)workbook.CreateSheet();
            HSSFRow headerRow = (HSSFRow)sheet.CreateRow(0);
            foreach (DataColumn column in SourceTable.Columns)
                headerRow.CreateCell(column.Ordinal).SetCellValue(column.ColumnName);
            int rowIndex = 1;
            foreach (DataRow row in SourceTable.Rows)
            {
                HSSFRow dataRow = (HSSFRow)sheet.CreateRow(rowIndex);
                foreach (DataColumn column in SourceTable.Columns)
                {
                    dataRow.CreateCell(column.Ordinal).SetCellValue(row[column].ToString());
                }
                rowIndex++;
            }

            workbook.Write(ms);
            ms.Flush();
            ms.Position = 0;
            sheet = null;
            headerRow = null;
            workbook = null;
            return ms;
        }

多Sheet：

private Stream RenderDataTableToExcel(DataTable[] dtSources)
        {
            HSSFWorkbook workbook = new HSSFWorkbook();
            MemoryStream ms = new MemoryStream();
            for (int k = 0; k < dtSources.Length; k++)
            {
                HSSFSheet sheet = (HSSFSheet)workbook.CreateSheet(dtSources[k].TableName.ToString());

                //填充表头
                HSSFRow dataRow = (HSSFRow)sheet.CreateRow(0);
                foreach (DataColumn column in dtSources[k].Columns)
                {
                    dataRow.CreateCell(column.Ordinal).SetCellValue(column.ColumnName);
                }

                //填充内容
                for (int i = 0; i < dtSources[k].Rows.Count; i++)
                {
                    dataRow = (HSSFRow)sheet.CreateRow(i + 1);
                    for (int j = 0; j < dtSources[k].Columns.Count; j++)
                    {
                        dataRow.CreateCell(j).SetCellValue(dtSources[k].Rows[i][j].ToString());
                    }
                }
            }

            workbook.Write(ms);
            ms.Flush();
            ms.Position = 0;
            return ms;
        }

4：导出Excel

Response.AddHeader("Content-Disposition", string.Format("attachment;filename="+fileName+".xls"));
Response.BinaryWrite(ms.ToArray());
ms.Close();
ms.Dispose();

Response.AddHeader("Content-Disposition", "attachment; filename="+System.Web.HttpUtility.UrlEncode("中文",System.Text.Encoding.UTF8)+".xls");

5：Oracle中sql语句 输出保留2位小数的操作：

CASE NVL(SUM(ES_ElmTotal),0) when 0 then '0.00%' else  round(NVL(SUM(ES_ExtElmTotalNum),0)*100/NVL(SUM(ES_ElmTotal),0),2)||'%' end  AS 总体扩展率