NPOI DataSet导出excel

        /// <summary>

        /// DataSet导出到Excel的MemoryStream

        /// </summary>

        /// <param name="dtSource">源DataSet</param>

        public static MemoryStream DataSetToExcel(DataSet ds)

        {

            XSSFWorkbook workbook = new XSSFWorkbook();

            for (int k = ; k < ds.Tables.Count; k++)

            {

                //   HSSFSheet sheet = (HSSFSheet)workbook.CreateSheet();

                XSSFSheet sheet = (XSSFSheet)workbook.CreateSheet(ds.Tables[k].TableName.ToString());

                #region 右击文件 属性信息

                {

                    DocumentSummaryInformation dsi = PropertySetFactory.CreateDocumentSummaryInformation();

                    dsi.Company = "NPOI";

                    // workbook.DocumentSummaryInformation = dsi;

                    SummaryInformation si = PropertySetFactory.CreateSummaryInformation();

                    si.Author = "文件作者信息"; //填加xls文件作者信息

                    si.ApplicationName = "创建程序信息"; //填加xls文件创建程序信息

                    si.LastAuthor = "最后保存者信息"; //填加xls文件最后保存者信息

                    si.Comments = "作者信息"; //填加xls文件作者信息

                    si.Title = "标题信息"; //填加xls文件标题信息

                    si.Subject = "主题信息";//填加文件主题信息

                    si.CreateDateTime = System.DateTime.Now;

                    // workbook.SummaryInformation = si;

                }

                #endregion

                XSSFCellStyle dateStyle = (XSSFCellStyle)workbook.CreateCellStyle();

                XSSFDataFormat format = (XSSFDataFormat)workbook.CreateDataFormat();

                dateStyle.DataFormat = format.GetFormat("yyyy-mm-dd");

                //取得列宽

                /*

                int[] arrColWidth = new int[dtSource.Columns.Count];

                foreach (DataColumn item in dtSource.Columns)

                {

                    arrColWidth[item.Ordinal] = Encoding.GetEncoding(936).GetBytes(item.ColumnName.ToString()).Length;

                }

                for (int i = 0; i < dtSource.Rows.Count; i++)

                {

                    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;

                        }

                    }

                }

                 */

                int rowIndex = ;

                foreach (DataRow row in ds.Tables[k].Rows)

                {

                    #region 新建表，填充表头，填充列头，样式

                    if (rowIndex == )

                    {

                        //if (rowIndex != 0)

                        //{

                        //    sheet = (XSSFSheet)workbook.CreateSheet();

                        //}

                        #region 表头及样式

                        {

                            //XSSFRow headerRow = (XSSFRow)sheet.CreateRow(0);

                            //headerRow.HeightInPoints = 25;

                            //headerRow.CreateCell(0).SetCellValue(strHeaderText);

                            //HSSFCellStyle headStyle = (HSSFCellStyle)workbook.CreateCellStyle();

                            ////  headStyle.Alignment = CellHorizontalAlignment.CENTER;

                            //HSSFFont font = (HSSFFont)workbook.CreateFont();

                            //font.FontHeightInPoints = 20;

                            //font.Boldweight = 700;

                            //headStyle.SetFont(font);

                            //headerRow.GetCell(0).CellStyle = headStyle;

                            //// sheet.AddMergedRegion(new Region(0, 0, 0, dtSource.Columns.Count - 1));

                            ////headerRow.Dispose();

                        }

                        #endregion

                        #region 列头及样式

                        {

                            XSSFRow headerRow = (XSSFRow)sheet.CreateRow();

                            XSSFCellStyle headStyle = (XSSFCellStyle)workbook.CreateCellStyle();

                            //headStyle.Alignment = CellHorizontalAlignment.CENTER;

                            XSSFFont font = (XSSFFont)workbook.CreateFont();

                            font.FontHeightInPoints = ;

                            font.Boldweight = ;

                            headStyle.SetFont(font);

                            foreach (DataColumn column in ds.Tables[k].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);

                            }

                            // headerRow.Dispose();

                        }

                        #endregion

                        rowIndex = ;

                    }

                    #endregion

                    #region 填充内容

                    XSSFRow dataRow = (XSSFRow)sheet.CreateRow(rowIndex);

                    foreach (DataColumn column in ds.Tables[k].Columns)

                    {

                        XSSFCell newCell = (XSSFCell)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

                                System.DateTime dateV;

                                System.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();

                return ms;

            }

        }

/// DataSet导出到Excel的MemoryStream

        /// <summary>

        /// DataSet导出到Excel文件

        /// </summary>

        /// <param name="dtSource">源DataSet</param>

        /// <param name="strFileName">保存位置</param>

        public static void DataSetToExcel(DataSet dtSource, string strFileName)

        {

            using (MemoryStream ms = DataSetToExcel(dtSource ))

            {

                using (FileStream fs = new FileStream(strFileName, FileMode.Create, FileAccess.Write))

                {

                    byte[] data = ms.ToArray();

                    fs.Write(data, , data.Length);

                    fs.Flush();

                }

            }

        }