NPOI导入导出Excel

.net mvc利用NPOI导入导出excel

1、导出Excel ：
首先引用NPOI包，从这里下载》download
（Action一定要用FileResult）

/// <summary>
        /// 批量导出需要导出的列表
        /// </summary>
        /// <returns></returns>
        public FileResult ExportStu2()
        {
            //获取list数据
            var checkList = (from oc in db.OrganizeCustoms
                            join o in db.Organizes.DefaultIfEmpty() on oc.custom_id equals o.id
                            where oc.organize_id == 1
                            select new
                            {
                                customer_id = o.id,
                                customer_name = o.name
                            }).ToList();

            //创建Excel文件的对象
            NPOI.HSSF.UserModel.HSSFWorkbook book = new NPOI.HSSF.UserModel.HSSFWorkbook();
            //添加一个sheet
            NPOI.SS.UserModel.ISheet sheet1 = book.CreateSheet("Sheet1");

            //貌似这里可以设置各种样式字体颜色背景等，但是不是很方便，这里就不设置了

            //给sheet1添加第一行的头部标题
            NPOI.SS.UserModel.IRow row1 = sheet1.CreateRow(0);
            row1.CreateCell(0).SetCellValue("编号");
            row1.CreateCell(1).SetCellValue("姓名");
            //....N行

            //将数据逐步写入sheet1各个行
            for (int i = 0; i < checkList.Count; i++)
            {
                NPOI.SS.UserModel.IRow rowtemp = sheet1.CreateRow(i + 1);
                rowtemp.CreateCell(0).SetCellValue(checkList[i].customer_id.ToString());
                rowtemp.CreateCell(1).SetCellValue(checkList[i].customer_name.ToString());
                //....N行
            }
            // 写入到客户端
            System.IO.MemoryStream ms = new System.IO.MemoryStream();
            book.Write(ms);
            ms.Seek(0, SeekOrigin.Begin);
            DateTime dt = DateTime.Now;
            string dateTime = dt.ToString("yyMMddHHmmssfff");
            string fileName = "查询结果" + dateTime + ".xls";
            return File(ms, "application/vnd.ms-excel", fileName);
        }

前台直接写就可实现：

@Html.ActionLink("点击导出Excel", "ExportStu2")

这里有一篇专门介绍设置样式的文章：
http://www.cnblogs.com/puzi0315/p/3265958.html
http://blog.csdn.net/xhccom/article/details/7687264
http://blog.csdn.net/bestreally/article/details/23257851
2、导入Excel：
首先说一些前台吧，mvc上传注意必须加 new { enctype = "multipart/form-data" }

<td>
    @using (@Html.BeginForm("ImportStu", "ProSchool", FormMethod.Post, new { enctype = "multipart/form-data" }))
    {
        <text>选择上传文件：（工作表名为“Sheet1”，“电脑号”在A1单元格。）</text>
        <input name="file" type="file" id="file" />
        <input type="submit" name="Upload" value="批量导入第一批名册" />
    }
</td>

后台实现：只传路径得出DataTable：

/// <summary>
    /// Excel导入
    /// </summary>
    /// <param name="filePath"></param>
    /// <returns></returns>
    public DataTable ImportExcelFile(string filePath)
    {
      HSSFWorkbook hssfworkbook;
      #region//初始化信息
      try
      {
        using (FileStream file = new FileStream(filePath, FileMode.Open, FileAccess.Read))
        {
          hssfworkbook = new HSSFWorkbook(file);
        }
      }
      catch (Exception e)
      {
        throw e;
      }
      #endregion

      using (NPOI.SS.UserModel.ISheet sheet = hssfworkbook.GetSheetAt(0))
      {
        DataTable table = new DataTable();
        IRow headerRow = sheet.GetRow(0);//第一行为标题行
        int cellCount = headerRow.LastCellNum;//LastCellNum = PhysicalNumberOfCells
        int rowCount = sheet.LastRowNum;//LastRowNum = PhysicalNumberOfRows - 1

        //handling header.
        for (int i = headerRow.FirstCellNum; i < cellCount; i++)
        {
          DataColumn column = new DataColumn(headerRow.GetCell(i).StringCellValue);
          table.Columns.Add(column);
        }
        for (int i = (sheet.FirstRowNum + 1); i <= rowCount; i++)
        {
          IRow row = sheet.GetRow(i);
          DataRow dataRow = table.NewRow();

          if (row != null)
          {
            for (int j = row.FirstCellNum; j < cellCount; j++)
            {
              if (row.GetCell(j) != null)
                dataRow[j] = GetCellValue(row.GetCell(j));
            }
          }
          table.Rows.Add(dataRow);
        }
        return table;
      }
    }

补充一个类：

/// <summary>
    /// 根据Excel列类型获取列的值
    /// </summary>
    /// <param name="cell">Excel列</param>
    /// <returns></returns>
    private static string GetCellValue(ICell cell)
    {
      if (cell == null){ return string.Empty; }
      switch (cell.CellType)
      {
        case CellType.BLANK:
          return string.Empty;
        case CellType.BOOLEAN:
          return cell.BooleanCellValue.ToString();
        case CellType.ERROR:
          return cell.ErrorCellValue.ToString();
        case CellType.NUMERIC:
        case CellType.Unknown:
        default:
          return cell.ToString();//This is a trick to get the correct value of the cell. NumericCellValue will return a numeric value no matter the cell value is a date or a number
        case CellType.STRING:
          return cell.StringCellValue;
        case CellType.FORMULA:
          try
          {
            HSSFFormulaEvaluator e = new HSSFFormulaEvaluator(cell.Sheet.Workbook);
            e.EvaluateInCell(cell);
            return cell.ToString();
          }
          catch
          {
            return cell.NumericCellValue.ToString();
          }
      }
    }

得到DataTable后，就想怎么操作就怎么操作了。