通过NPOI操作Excel

最近在做的一个项目中需要生成Excel，通过学习使用NPOI实现了相关需求，写了一个简便操作的类，记录如下：

public class NPOIHelperForExcel
    {
        #region excel文件属性

        //作者
        public string Author { get; set; }

        //标题
        public string Title { get; set; }

        //主题
        public string Subject { get; set; }

        //标记
        public string Keywords { get; set; }

        //创建程序信息
        public string ApplicationName { get; set; }

        //最后一次保存者
        public string LastAuthor { get; set; }

        //备注
        public string Comments { get; set; }

        //创建内容的时间
        public DateTime? CreateDateTime { get; set; }

        //最后一次打印的时间
        public DateTime? LastPrinted { get; set; }

        //最后一次保存的时间
        public DateTime? LastSaveDateTime { get; set; }

        //公司
        public string Company { get; set; }

        //管理者
        public string Manager { get; set; }

        //比例
        public bool Scale { get; set; }

        #endregion

        #region 导出，将DataTable导出为Excel文件
        /// <summary>
        /// DataTable导出到Excel文件
        /// </summary>
        /// <param name="dtSource">源DataTable</param>
        /// <param name="headerTextList">表头摘要信息</param>
        /// <param name="strFileName">保存位置</param>
        public void Export(DataTable dtSource, List<String> headerTextList, string strFileName)
        {
            using (MemoryStream ms = Export(dtSource, headerTextList))
            {
                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="headerTextList">表头摘要信息</param>
        public MemoryStream Export(DataTable dtSource, List<String> headerTextList)
        {
            HSSFWorkbook workbook = new HSSFWorkbook();
            ISheet sheet = workbook.CreateSheet("sheet1");

            //设置Excel文件属性信息
            SetFileProperty(workbook);

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

            //计算列宽
            int[] arrColWidth = new int[dtSource.Columns.Count];
            foreach (DataColumn item in dtSource.Columns)
            {
                arrColWidth[item.Ordinal] = Encoding.GetEncoding().GetBytes(item.ColumnName.ToString()).Length;
            }
            //获取每一列的最大列宽
            for (int i = ; i < dtSource.Rows.Count; i++)
            {
                for (int j = ; j < dtSource.Columns.Count; j++)
                {
                    int intTemp = Encoding.GetEncoding().GetBytes(dtSource.Rows[i][j].ToString()).Length;
                    if (intTemp > arrColWidth[j])
                    {
                        arrColWidth[j] = intTemp;
                    }
                }
            }

            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();
                    }

                    #region 表头及样式
                    for (int i = ; i < headerTextList.Count; i++)
                    {
                        HSSFRow headerRow = (HSSFRow)sheet.CreateRow(i);
                        headerRow.HeightInPoints = ;
                        headerRow.CreateCell().SetCellValue(headerTextList[i]);

                        HSSFCellStyle headerStyle = (HSSFCellStyle)workbook.CreateCellStyle();
                        headerStyle.Alignment = HorizontalAlignment.Left;
                        HSSFFont font = (HSSFFont)workbook.CreateFont();
                        font.FontHeightInPoints = ;
                        //font.Boldweight = 700;
                        headerStyle.SetFont(font);
                        headerRow.GetCell().CellStyle = headerStyle;
                        sheet.AddMergedRegion(new CellRangeAddress(, , , dtSource.Columns.Count - ));
                    }
                    #endregion

                    #region 列头及样式
                    {
                        HSSFRow headerRow = (HSSFRow)sheet.CreateRow(headerTextList.Count);
                        HSSFCellStyle headStyle = (HSSFCellStyle)workbook.CreateCellStyle();
                        headStyle.Alignment = HorizontalAlignment.Center;
                        HSSFFont font = (HSSFFont)workbook.CreateFont();
                        font.FontHeightInPoints = ;
                        font.Boldweight = ;
                        headStyle.SetFont(font);
                        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] + ) * );
                        }
                    }
                    #endregion

                    rowIndex = headerTextList.Count + ;
                }

                #endregion

                #region 填充表格内容

                HSSFRow dataRow = (HSSFRow)sheet.CreateRow(rowIndex);
                foreach (DataColumn column in dtSource.Columns)
                {
                    HSSFCell newCell = (HSSFCell)dataRow.CreateCell(column.Ordinal);

                    string drValue = row[column].ToString();

                    switch (column.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 = ;

                return ms;
            }

        }

        /// <summary>
        /// 用于Web导出
        /// </summary>
        /// <param name="dtSource">源DataTable</param>
        /// <param name="headerTextList">表头摘要信息</param>
        /// <param name="strFileName">文件名</param>
        public void ExportByWeb(DataTable dtSource, List<String> headerTextList, string strFileName)
        {
            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, headerTextList).GetBuffer());
            curContext.Response.End();
        }
        #endregion

        #region 导入，将excel读取到DataTable中
        /// <summary>
        /// 读取excel,默认第一行为表头
        /// </summary>
        /// <param name="strFileName">excel文件路径</param>
        /// <returns>DataTable</returns>
        public DataTable Import(string strFileName)
        {
            return Import(strFileName, );
        }

        /// <summary>
        /// 读取excel
        /// </summary>
        /// <param name="strFileName">excel文件路径</param>
        /// <param name="sheetNum">sheet索引，以0开始</param>
        /// <returns>DataTable</returns>
        public DataTable Import(string strFileName, int sheetNum)
        {
            return Import(strFileName, sheetNum, , );
        }

        /// <summary>
        /// 读取excel
        /// </summary>
        /// <param name="strFileName">excel文件路径</param>
        /// <param name="sheetNum">sheet索引，以0开始</param>
        /// <param name="startRowNum">起始行号，即：表头在Excel中的行号</param>
        /// <param name="startColNum">起始列号</param>
        /// <returns>DataTable</returns>
        public DataTable Import(string strFileName, int sheetNum, int startRowNum, int startColNum)
        {
            return Import(strFileName, sheetNum, startRowNum, -, startColNum, -);
        }

        /// <summary>
        /// 读取excel
        /// sheet.LastRowNum属性获取的是Excel中该工作表(sheet)的末行行号减1；
        /// headerRow.LastCellNum属性获取的是Excel中该行的列数
        /// </summary>
        /// <param name="strFileName">excel文档路径</param>
        /// <param name="sheetNum">工作表索引，以0开始</param>
        /// <param name="startRowNum">起始行号，即：表头在Excel中的行号</param>
        /// <param name="endRowNum">结束行号</param>
        /// <param name="startColNum">起始列号</param>
        /// <param name="endColNum">结束列号</param>
        /// <returns>DataTable</returns>
        public DataTable Import(string strFileName, int sheetNum, int startRowNum, int endRowNum, int startColNum, int endColNum)
        {
            DataTable dt = new DataTable();

            HSSFWorkbook hssfworkbook;
            using (FileStream file = new FileStream(strFileName, FileMode.Open, FileAccess.Read))
            {
                hssfworkbook = new HSSFWorkbook(file);
            }

            int sheetCount = hssfworkbook.NumberOfSheets;

            sheetNum = sheetNum <  || sheetNum > sheetCount -  ?  : sheetNum;

            HSSFSheet sheet = (HSSFSheet)hssfworkbook.GetSheetAt(sheetNum);

            HSSFRow headerRow = null;

            #region 行列号范围验证

            startColNum = startColNum <  ?  : startColNum;

            startRowNum = startRowNum <  ?  : startRowNum;

            headerRow = (HSSFRow)sheet.GetRow(startRowNum - );

            endColNum = (endColNum > headerRow.LastCellNum || endColNum < ) ? headerRow.LastCellNum : endColNum;

            endRowNum = (endRowNum -  > sheet.LastRowNum || endRowNum < ) ? sheet.LastRowNum +  : endColNum;

            #endregion

            //添加列
            for (int j = startColNum - ; j < endColNum; j++)
            {
                HSSFCell cell = (HSSFCell)headerRow.GetCell(j);
                dt.Columns.Add(cell.ToString());
            }

            //添加行
            for (int i = startRowNum; i <= endRowNum - ; i++)
            {
                HSSFRow row = (HSSFRow)sheet.GetRow(i);
                DataRow dataRow = dt.NewRow();

                for (int j = startColNum - ; j < endColNum; j++)
                {
                    if (row.GetCell(j) != null)
                        dataRow[j - startColNum + ] = row.GetCell(j).ToString();
                }

                dt.Rows.Add(dataRow);
            }
            return dt;
        }
        #endregion

        #region 单元格写入
        ///// <summary>
        ///// 给指定单元格写入内容
        ///// </summary>
        ///// <param name="workBook"></param>
        ///// <param name="sheetName"></param>
        ///// <param name="rowNum"></param>
        ///// <param name="colNum"></param>
        ///// <param name="content"></param>
        //public void WriteCell(HSSFWorkbook workBook, string sheetName, int rowNum, int colNum, string content)
        //{
        //    if (workBook == null)
        //    {
        //        throw new Exception("workBook不能为null");
        //    }
        //    WriteCell(workBook, workBook.GetSheetIndex(sheetName), rowNum, colNum, content);
        //}

        ///// <summary>
        ///// 给指定单元格写入内容
        ///// </summary>
        ///// <param name="workBook"></param>
        ///// <param name="sheetNum"></param>
        ///// <param name="rowNum"></param>
        ///// <param name="colNum"></param>
        ///// <param name="content"></param>
        ///// <returns></returns>
        //public void WriteCell(HSSFWorkbook workBook, int sheetNum, int rowNum, int colNum, string content)
        //{
        //    if (workBook == null)
        //    {
        //        throw new Exception("workBook不能为null");
        //    }

        //    if (workBook.NumberOfSheets < sheetNum || sheetNum < 0)
        //    {
        //        throw new Exception("指定的sheet不存在");
        //    }

        //    ISheet sheet = workBook.GetSheetAt(sheetNum - 1);

        //    HSSFRow row = (HSSFRow)sheet.GetRow(rowNum) ?? (HSSFRow)sheet.CreateRow(rowNum - 1);
        //    HSSFCell cell = (HSSFCell)row.CreateCell(6);
        //    cell.SetCellValue(content);

        //    //using (MemoryStream ms = new MemoryStream())
        //    //{
        //    //    workBook.Write(ms);
        //    //    ms.Flush();
        //    //    ms.Position = 0;

        //    //    using (FileStream fs = new FileStream("测试行列写入.xls", FileMode.Create, FileAccess.Write))
        //    //    {
        //    //        byte[] data = ms.ToArray();
        //    //        fs.Write(data, 0, data.Length);
        //    //        fs.Flush();
        //    //    }
        //    //}
        //    //return workBook;
        //}
        #endregion

        /// <summary>
        /// 设置Excel文件属性信息
        /// </summary>
        /// <param name="workbook"></param>
        private void SetFileProperty(HSSFWorkbook workbook)
        {

DocumentSummaryInformation dsi = PropertySetFactory.CreateDocumentSummaryInformation();
dsi.Company = this.Company ?? "";
dsi.Scale = this.Scale;
dsi.Manager = this.Manager ?? "";
workbook.DocumentSummaryInformation = dsi;

SummaryInformation si = PropertySetFactory.CreateSummaryInformation();
si.Author = this.Author ?? "";
si.ApplicationName = this.ApplicationName ?? "";
si.LastAuthor = this.LastAuthor ?? "";
si.Comments = this.Comments ?? "";
si.Title = this.Title ?? "";
si.Subject = this.Subject ?? "";
si.CreateDateTime = this.CreateDateTime ?? DateTime.Now;
si.Keywords = this.Keywords ?? "";
si.LastAuthor = this.LastAuthor ?? "";
si.LastPrinted = this.LastPrinted ?? DateTime.Now;
si.LastSaveDateTime = this.LastSaveDateTime ?? DateTime.Now;

//上面的属性必须赋值，不能为null，不然执行到Export方法的"workbook.Write(ms);"处会导致空引用错误。

workbook.SummaryInformation = si;

        }
    }