C#利用NOPI处理Excel的代码

using System;
using System.Data;
using System.IO;
using System.Text;
using System.Web;
using NPOI.HPSF;
using NPOI.HSSF.UserModel;
using NPOI.SS.UserModel;  

public class ExcelHelper
{
    /// <summary>
    /// DataTable导出到Excel文件
    /// </summary>
    /// <param name="dtSource">源DataTable</param>
    /// <param name="strHeaderText">表头文本</param>
    /// <param name="strFileName">保存位置</param>
    /// <param name="strSheetName">工作表名称</param>
    /// <Author>柳永法 http://www.yongfa365.com/ 2010-5-8 22:21:41</Author>
    public static void Export(DataTable dtSource, string strHeaderText, string strFileName, string strSheetName, string[] oldColumnNames, string[] newColumnNames)
    {
        if (strSheetName == "")
        {
            strSheetName = "Sheet";
        }
        using (MemoryStream ms = Export(dtSource, strHeaderText, strSheetName, oldColumnNames, newColumnNames))
        {
            using (FileStream fs = new FileStream(strFileName, FileMode.Create, FileAccess.Write))
            {
                byte[] data = ms.ToArray();
                fs.Write(data, , data.Length);
                fs.Flush();
            }
        }
    }  

    /// <summary>
    /// DataTable导出到Excel的MemoryStream
    /// </summary>
    /// <param name="dtSource">源DataTable</param>
    /// <param name="strHeaderText">表头文本</param>
    /// <param name="strSheetName">工作表名称</param>
    /// <Author>柳永法 http://www.yongfa365.com/ 2010-5-8 22:21:41</Author>
    public static MemoryStream Export(DataTable dtSource, string strHeaderText, string strSheetName, string[] oldColumnNames, string[] newColumnNames)
    {
        if (oldColumnNames.Length != newColumnNames.Length)
        {
            return new MemoryStream();
        }
        HSSFWorkbook workbook = new HSSFWorkbook();
        //HSSFSheet sheet = workbook.CreateSheet();// workbook.CreateSheet();
        ISheet sheet = workbook.CreateSheet(strSheetName);  

        #region 右击文件 属性信息
        {
            DocumentSummaryInformation dsi = PropertySetFactory.CreateDocumentSummaryInformation();
            dsi.Company = "http://....../";
            workbook.DocumentSummaryInformation = dsi;  

            SummaryInformation si = PropertySetFactory.CreateSummaryInformation();
            if (HttpContext.Current.Session["realname"] != null)
            {
                si.Author = HttpContext.Current.Session["realname"].ToString();
            }
            else
            {
                if (HttpContext.Current.Session["username"] != null)
                {
                    si.Author = HttpContext.Current.Session["username"].ToString();
                }
            }                                       //填加xls文件作者信息
            si.ApplicationName = "NPOI";            //填加xls文件创建程序信息
            si.LastAuthor = "OA系统";           //填加xls文件最后保存者信息
            si.Comments = "OA系统自动创建文件";      //填加xls文件作者信息
            si.Title = strHeaderText;               //填加xls文件标题信息
            si.Subject = strHeaderText;              //填加文件主题信息
            si.CreateDateTime = DateTime.Now;
            workbook.SummaryInformation = si;
        }
        #endregion  

        ICellStyle dateStyle = workbook.CreateCellStyle();
        IDataFormat format = workbook.CreateDataFormat();
        dateStyle.DataFormat = format.GetFormat("yyyy-mm-dd");  

        #region 取得列宽
        int[] arrColWidth = new int[oldColumnNames.Length];
        for (int i = ; i < oldColumnNames.Length; i++)
        {
            arrColWidth[i] = Encoding.GetEncoding().GetBytes(newColumnNames[i]).Length;
        }
        /*
        foreach (DataColumn item in dtSource.Columns)
        {
            arrColWidth[item.Ordinal] = Encoding.GetEncoding(936).GetBytes(item.ColumnName.ToString()).Length;
        }
         * */  

        for (int i = ; i < dtSource.Rows.Count; i++)
        {
            for (int j = ; j < oldColumnNames.Length; j++)
            {
                int intTemp = Encoding.GetEncoding().GetBytes(dtSource.Rows[i][oldColumnNames[j]].ToString()).Length;
                if (intTemp > arrColWidth[j])
                {
                    arrColWidth[j] = intTemp;
                }
            }
            /*
            for (int j = 0; j < dtSource.Columns.Count; j++)
            {
                int intTemp = Encoding.GetEncoding(936).GetBytes(dtSource.Rows[i][j].ToString()).Length;
                if (intTemp > arrColWidth[j])
                {
                    arrColWidth[j] = intTemp;
                }
            }
             * */
        }
        #endregion
        int rowIndex = ;  

        foreach (DataRow row in dtSource.Rows)
        {
            #region 新建表，填充表头，填充列头，样式
            if (rowIndex ==  || rowIndex == )
            {
                if (rowIndex != )
                {
                    sheet = workbook.CreateSheet(strSheetName + ((int)rowIndex/).ToString());
                }  

                #region 表头及样式
                {
                    IRow headerRow = sheet.CreateRow();
                    headerRow.HeightInPoints = ;
                    headerRow.CreateCell().SetCellValue(strHeaderText);  

                    ICellStyle headStyle = workbook.CreateCellStyle();
                    headStyle.Alignment = HorizontalAlignment.CENTER;
                    IFont font = workbook.CreateFont();
                    font.FontHeightInPoints = ;
                    font.Boldweight = ;
                    headStyle.SetFont(font);  

                    headerRow.GetCell().CellStyle = headStyle;
                    //sheet.AddMergedRegion(new Region(0, 0, 0, dtSource.Columns.Count - 1));
                    sheet.AddMergedRegion(new NPOI.SS.Util.CellRangeAddress(, , , dtSource.Columns.Count - ));
                }
                #endregion  

                #region 列头及样式
                {
                    //HSSFRow headerRow = sheet.CreateRow(1);
                    IRow headerRow = sheet.CreateRow();  

                    ICellStyle headStyle = workbook.CreateCellStyle();
                    headStyle.Alignment = HorizontalAlignment.CENTER;
                    IFont font = workbook.CreateFont();
                    font.FontHeightInPoints = ;
                    font.Boldweight = ;
                    headStyle.SetFont(font);  

                    for (int i = ; i < oldColumnNames.Length; i++)
                    {
                        headerRow.CreateCell(i).SetCellValue(newColumnNames[i]);
                        headerRow.GetCell(i).CellStyle = headStyle;
                        //设置列宽
                        sheet.SetColumnWidth(i, (arrColWidth[i] + ) * );
                    }
                    /*
                    foreach (DataColumn column in dtSource.Columns)
                    {
                        headerRow.CreateCell(column.Ordinal).SetCellValue(column.ColumnName);
                        headerRow.GetCell(column.Ordinal).CellStyle = headStyle; 

                        //设置列宽
                        sheet.SetColumnWidth(column.Ordinal, (arrColWidth[column.Ordinal] + 1) * 256);
                    }
                     * */
                }
                #endregion  

                rowIndex = ;
            }
            #endregion  

            #region 填充内容
            IRow dataRow = sheet.CreateRow(rowIndex);
            //foreach (DataColumn column in dtSource.Columns)
            for(int i=;i<oldColumnNames.Length;i++)
            {
                ICell newCell = dataRow.CreateCell(i);  

                string drValue = row[oldColumnNames[i]].ToString();  

                switch (dtSource.Columns[oldColumnNames[i]].DataType.ToString())
                {
                    case "System.String"://字符串类型
                        newCell.SetCellValue(drValue);
                        break;
                    case "System.DateTime"://日期类型
                        DateTime dateV;
                        DateTime.TryParse(drValue, out dateV);
                        newCell.SetCellValue(dateV);  

                        newCell.CellStyle = dateStyle;//格式化显示
                        break;
                    case "System.Boolean"://布尔型
                        bool boolV = false;
                        bool.TryParse(drValue, out boolV);
                        newCell.SetCellValue(boolV);
                        break;
                    case "System.Int16"://整型
                    case "System.Int32":
                    case "System.Int64":
                    case "System.Byte":
                        int intV = ;
                        int.TryParse(drValue, out intV);
                        newCell.SetCellValue(intV);
                        break;
                    case "System.Decimal"://浮点型
                    case "System.Double":
                        double doubV = ;
                        double.TryParse(drValue, out doubV);
                        newCell.SetCellValue(doubV);
                        break;
                    case "System.DBNull"://空值处理
                        newCell.SetCellValue("");
                        break;
                    default:
                        newCell.SetCellValue("");
                        break;
                }  

            }
            #endregion  

            rowIndex++;
        }  

        using (MemoryStream ms = new MemoryStream())
        {
            workbook.Write(ms);
            ms.Flush();
            ms.Position = ;  

            //sheet.Dispose();
            sheet = null;
            workbook = null;
            //workbook.Dispose();//一般只用写这一个就OK了，他会遍历并释放所有资源，但当前版本有问题所以只释放sheet
            return ms;
        }
    }  

    /// <summary>
    /// WEB导出DataTable到Excel
    /// </summary>
    /// <param name="dtSource">源DataTable</param>
    /// <param name="strHeaderText">表头文本</param>
    /// <param name="strFileName">文件名</param>
    /// <Author>柳永法 http://www.yongfa365.com/ 2010-5-8 22:21:41</Author>
    public static void ExportByWeb(DataTable dtSource, string strHeaderText, string strFileName)
    {
        ExportByWeb(dtSource, strHeaderText, strFileName, "sheet");
    }  

    /// <summary>
    /// WEB导出DataTable到Excel
    /// </summary>
    /// <param name="dtSource">源DataTable</param>
    /// <param name="strHeaderText">表头文本</param>
    /// <param name="strFileName">输出文件名，包含扩展名</param>
    /// <param name="oldColumnNames">要导出的DataTable列数组</param>
    /// <param name="newColumnNames">导出后的对应列名</param>
    public static void ExportByWeb(DataTable dtSource, string strHeaderText, string strFileName, string[] oldColumnNames, string[] newColumnNames)
    {
        ExportByWeb(dtSource, strHeaderText, strFileName, "sheet",oldColumnNames,newColumnNames);
    }  

    /// <summary>
    /// WEB导出DataTable到Excel
    /// </summary>
    /// <param name="dtSource">源DataTable</param>
    /// <param name="strHeaderText">表头文本</param>
    /// <param name="strFileName">输出文件名</param>
    /// <param name="strSheetName">工作表名称</param>
    public static void ExportByWeb(DataTable dtSource, string strHeaderText, string strFileName, string strSheetName)
    {
        HttpContext curContext = HttpContext.Current;  

        // 设置编码和附件格式
        curContext.Response.ContentType = "application/vnd.ms-excel";
        curContext.Response.ContentEncoding = Encoding.UTF8;
        curContext.Response.Charset = "";
        curContext.Response.AppendHeader("Content-Disposition",
            "attachment;filename=" + HttpUtility.UrlEncode(strFileName, Encoding.UTF8));  

        //生成列
        string columns = "";
        for (int i = ; i < dtSource.Columns.Count; i++)
        {
            if (i > )
            {
                columns += ",";
            }
            columns += dtSource.Columns[i].ColumnName;
        }  

        curContext.Response.BinaryWrite(Export(dtSource, strHeaderText,strSheetName,columns.Split(','),columns.Split(',')).GetBuffer());
        curContext.Response.End();  

    }  

    /// <summary>
    /// 导出DataTable到Excel
    /// </summary>
    /// <param name="dtSource">要导出的DataTable</param>
    /// <param name="strHeaderText">标题文字</param>
    /// <param name="strFileName">文件名，包含扩展名</param>
    /// <param name="strSheetName">工作表名</param>
    /// <param name="oldColumnNames">要导出的DataTable列数组</param>
    /// <param name="newColumnNames">导出后的对应列名</param>
    public static void ExportByWeb(DataTable dtSource, string strHeaderText, string strFileName, string strSheetName, string[] oldColumnNames, string[] newColumnNames)
    {
        HttpContext curContext = HttpContext.Current;  

        // 设置编码和附件格式
        curContext.Response.ContentType = "application/vnd.ms-excel";
        curContext.Response.ContentEncoding = Encoding.UTF8;
        curContext.Response.Charset = "";
        curContext.Response.AppendHeader("Content-Disposition",
            "attachment;filename=" + HttpUtility.UrlEncode(strFileName, Encoding.UTF8));  

        curContext.Response.BinaryWrite(Export(dtSource, strHeaderText, strSheetName,oldColumnNames,newColumnNames).GetBuffer());
        curContext.Response.End();
    }  

    /// <summary>读取excel
    /// 默认第一行为表头，导入第一个工作表
    /// </summary>
    /// <param name="strFileName">excel文档路径</param>
    /// <returns></returns>
    public static DataTable Import(string strFileName)
    {
        DataTable dt = new DataTable();  

        HSSFWorkbook hssfworkbook;
        using (FileStream file = new FileStream(strFileName, FileMode.Open, FileAccess.Read))
        {
            hssfworkbook = new HSSFWorkbook(file);
        }
        ISheet sheet = hssfworkbook.GetSheetAt();
        System.Collections.IEnumerator rows = sheet.GetRowEnumerator();  

        IRow headerRow = sheet.GetRow();
        int cellCount = headerRow.LastCellNum;  

        for (int j = ; j < cellCount; j++)
        {
            ICell cell = headerRow.GetCell(j);
            dt.Columns.Add(cell.ToString());
        }  

        for (int i = (sheet.FirstRowNum + ); i <= sheet.LastRowNum; i++)
        {
            IRow row = sheet.GetRow(i);
            DataRow dataRow = dt.NewRow();  

            for (int j = row.FirstCellNum; j < cellCount; j++)
            {
                if (row.GetCell(j) != null)
                    dataRow[j] = row.GetCell(j).ToString();
            }
            dt.Rows.Add(dataRow);
        }
        return dt;
    }
    /// <summary>
    /// 从Excel中获取数据到DataTable
    /// </summary>
    /// <param name="strFileName">Excel文件全路径(服务器路径)</param>
    /// <param name="SheetName">要获取数据的工作表名称</param>
    /// <param name="HeaderRowIndex">工作表标题行所在行号(从0开始)</param>
    /// <returns></returns>
    public static DataTable RenderDataTableFromExcel(string strFileName, string SheetName, int HeaderRowIndex)
    {
        using (FileStream file = new FileStream(strFileName, FileMode.Open, FileAccess.Read))
        {
            IWorkbook workbook = new HSSFWorkbook(file);
            return RenderDataTableFromExcel(workbook, SheetName, HeaderRowIndex);
        }
    }  

    /// <summary>
    /// 从Excel中获取数据到DataTable
    /// </summary>
    /// <param name="strFileName">Excel文件全路径(服务器路径)</param>
    /// <param name="SheetIndex">要获取数据的工作表序号(从0开始)</param>
    /// <param name="HeaderRowIndex">工作表标题行所在行号(从0开始)</param>
    /// <returns></returns>
    public static DataTable RenderDataTableFromExcel(string strFileName, int SheetIndex, int HeaderRowIndex)
    {
        using (FileStream file = new FileStream(strFileName, FileMode.Open, FileAccess.Read))
        {
            IWorkbook workbook = new HSSFWorkbook(file);
            string SheetName = workbook.GetSheetName(SheetIndex);
            return RenderDataTableFromExcel(workbook, SheetName, HeaderRowIndex);
        }
    }  

    /// <summary>
    /// 从Excel中获取数据到DataTable
    /// </summary>
    /// <param name="ExcelFileStream">Excel文件流</param>
    /// <param name="SheetName">要获取数据的工作表名称</param>
    /// <param name="HeaderRowIndex">工作表标题行所在行号(从0开始)</param>
    /// <returns></returns>
    public static DataTable RenderDataTableFromExcel(Stream ExcelFileStream, string SheetName, int HeaderRowIndex)
    {
        IWorkbook workbook = new HSSFWorkbook(ExcelFileStream);
        ExcelFileStream.Close();
        return RenderDataTableFromExcel(workbook, SheetName, HeaderRowIndex);
    }  

    /// <summary>
    /// 从Excel中获取数据到DataTable
    /// </summary>
    /// <param name="ExcelFileStream">Excel文件流</param>
    /// <param name="SheetIndex">要获取数据的工作表序号(从0开始)</param>
    /// <param name="HeaderRowIndex">工作表标题行所在行号(从0开始)</param>
    /// <returns></returns>
    public static DataTable RenderDataTableFromExcel(Stream ExcelFileStream, int SheetIndex, int HeaderRowIndex)
    {
        IWorkbook workbook = new HSSFWorkbook(ExcelFileStream);
        ExcelFileStream.Close();
        string SheetName = workbook.GetSheetName(SheetIndex);
        return RenderDataTableFromExcel(workbook, SheetName, HeaderRowIndex);
    }  

    /// <summary>
    /// 从Excel中获取数据到DataTable
    /// </summary>
    /// <param name="workbook">要处理的工作薄</param>
    /// <param name="SheetName">要获取数据的工作表名称</param>
    /// <param name="HeaderRowIndex">工作表标题行所在行号(从0开始)</param>
    /// <returns></returns>
    public static DataTable RenderDataTableFromExcel(IWorkbook workbook, string SheetName, int HeaderRowIndex)
    {
        ISheet sheet = workbook.GetSheet(SheetName);
        DataTable table = new DataTable();
        try
        {
            IRow headerRow = sheet.GetRow(HeaderRowIndex);
            int cellCount = headerRow.LastCellNum;  

            for (int i = headerRow.FirstCellNum; i < cellCount; i++)
            {
                DataColumn column = new DataColumn(headerRow.GetCell(i).StringCellValue);
                table.Columns.Add(column);
            }  

            int rowCount = sheet.LastRowNum;  

            #region 循环各行各列,写入数据到DataTable
            for (int i = (sheet.FirstRowNum + ); i < sheet.LastRowNum; i++)
            {
                IRow row = sheet.GetRow(i);
                DataRow dataRow = table.NewRow();
                for (int j = row.FirstCellNum; j < cellCount; j++)
                {
                    ICell cell = row.GetCell(j);
                    if (cell == null)
                    {
                        dataRow[j] = null;
                    }
                    else
                    {
                        //dataRow[j] = cell.ToString();
                        switch (cell.CellType)
                        {
                            case CellType.BLANK:
                                dataRow[j] = null;
                                break;
                            case CellType.BOOLEAN:
                                dataRow[j] = cell.BooleanCellValue;
                                break;
                            case CellType.NUMERIC:
                                dataRow[j] = cell.ToString();
                                break;
                            case CellType.STRING:
                                dataRow[j] = cell.StringCellValue;
                                break;
                            case CellType.ERROR:
                                dataRow[j] = cell.ErrorCellValue;
                                break;
                            case CellType.FORMULA:
                            default:
                                dataRow[j] = "=" + cell.CellFormula;
                                break;
                        }
                    }
                }
                table.Rows.Add(dataRow);
                //dataRow[j] = row.GetCell(j).ToString();
            }
            #endregion
        }
        catch (System.Exception ex)
        {
            table.Clear();
            table.Columns.Clear();
            table.Columns.Add("出错了");
            DataRow dr = table.NewRow();
            dr[] = ex.Message;
            table.Rows.Add(dr);
            return table;
        }
        finally
        {
            //sheet.Dispose();
            workbook = null;
            sheet = null;
        }
        #region 清除最后的空行
        for (int i = table.Rows.Count - ; i > ; i--)
        {
            bool isnull = true;
            for (int j = ; j < table.Columns.Count; j++)
            {
                if (table.Rows[i][j] != null)
                {
                    if (table.Rows[i][j].ToString() != "")
                    {
                        isnull = false;
                        break;
                    }
                }
            }
            if (isnull)
            {
                table.Rows[i].Delete();
            }
        }
        #endregion
        return table;
    }
}