NPOI帮助类

/// <summary>
    /// NPOI导出帮助类
    /// </summary>
    public class NPOIHelper
    {
        /// <summary>
        /// DataTable导出到Excel的MemoryStream
        /// </summary>
        /// <param name="dt">源DataTable</param>
        /// <param name="dicTableHeader">表头文本</param>
        private static MemoryStream Export(DataTable dt, Dictionary<string, string> dicTableHeader)
        {
            HSSFWorkbook workbook = new HSSFWorkbook();
            ISheet sheet = workbook.CreateSheet("工作表1");

            IRow headerRow = sheet.CreateRow();
            int headerIndex = ;

            ICellStyle headerCellStyle = Getcellstyle(workbook, stylexls.头);
            ICellStyle dateCellStyle = Getcellstyle(workbook, stylexls.时间);

            foreach (var item in dicTableHeader)
            {
                ICell cell = headerRow.CreateCell(headerIndex);
                cell.CellStyle = headerCellStyle;
                cell.SetCellValue(item.Value);
                headerIndex = headerIndex + ;
            }
            sheet.CreateFreezePane(, , , );

            int rowCount = dt.Rows.Count;
            for (int i = ; i < rowCount; i++)
            {
                IRow row = sheet.CreateRow(i + );
                int rowIndex = ;
                foreach (var item in dicTableHeader)
                {
                    ICell newCell = row.CreateCell(rowIndex);
                    rowIndex = rowIndex + ;
                    DataColumn dc = dt.Columns[item.Key];
                    string drValue = dt.Rows[i][item.Key].ToString();
                    switch (dc.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 = dateCellStyle;//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;
                    }
                }
            }
            ////自动列宽
            //for (int i = 0; i <= dicTableHeader.Count; i++)
            //    sheet.AutoSizeColumn(i, true);

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

        /// <summary>
        /// DataTable导出到Excel的MemoryStream
        /// </summary>
        /// <param name="dt">数据源DataTable</param>
        /// <param name="heardList">头部列表</param>
        /// <returns></returns>
        private static MemoryStream Export(DataTable dt, IList<SYS_DICT> heardList)
        {
            HSSFWorkbook workbook = new HSSFWorkbook();
            ISheet sheet = workbook.CreateSheet("工作表1");

            ICellStyle headerCellStyle = Getcellstyle(workbook, stylexls.头);
            ICellStyle dateCellStyle = Getcellstyle(workbook, stylexls.时间);

            IRow headerRow = sheet.CreateRow();
            int headerIndex = ;
            foreach (var item in heardList)
            {
                ICell cell = headerRow.CreateCell(headerIndex);
                cell.CellStyle = headerCellStyle;
                cell.SetCellValue(item.fname_ch);
                headerIndex = headerIndex + ;
            }
            sheet.CreateFreezePane(, , , );

            int rowCount = dt.Rows.Count;
            for (int i = ; i < rowCount; i++)
            {
                IRow row = sheet.CreateRow(i + );
                int rowIndex = ;
                foreach (var item in heardList)
                {
                    ICell newCell = row.CreateCell(rowIndex);
                    rowIndex = rowIndex + ;
                    DataColumn dc = dt.Columns[item.field_name];
                    string drValue = dt.Rows[i][item.field_name].ToString();
                    switch (dc.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 = dateCellStyle;//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;
                    }
                }
            }
            ////自动列宽
            //for (int i = 0; i <= dicTableHeader.Count; i++)
            //    sheet.AutoSizeColumn(i, true);

            int heardListLen = heardList.Count;
            for (int i = ; i < heardListLen; i++)
            {
                int width = ;
                int.TryParse(heardList[i].ExcelColWidth.ToString(), out width);
                width = (int)((width + 0.72) * );
                sheet.SetColumnWidth(i, width);
            }

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

        /// <summary>
        /// 用于Web导出
        /// </summary>
        /// <param name="dt">数据源DataTable</param>
        /// <param name="strFileName">文件名</param>
        /// <param name="dicTableHeader">导出对照</param>
        public static void ExportByWeb(DataTable dt, string strFileName, Dictionary<string, string> dicTableHeader)
        {
            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 = "";
            strFileName = strFileName + DateTime.Now.ToString("yyyyMMddHHmmss");
            string fileName = HttpUtility.UrlEncode(strFileName, Encoding.UTF8) + ".xls";
            curContext.Response.AppendHeader("Content-Disposition",
                "attachment;filename=" + fileName);

            curContext.Response.BinaryWrite(Export(dt, dicTableHeader).GetBuffer());
            curContext.Response.End();
        }

        /// <summary>
        /// Web Excel导出
        /// </summary>
        /// <param name="dt">数据源DataTable</param>
        /// <param name="strFileName">文件名</param>
        /// <param name="heardList">头部列表</param>
        public static void ExportByWeb(DataTable dt, string strFileName, IList<SYS_DICT> heardList)
        {
            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 = "";
            strFileName = strFileName + DateTime.Now.ToString("yyyyMMddHHmmss");
            string fileName = HttpUtility.UrlEncode(strFileName, Encoding.UTF8) + ".xls";
            curContext.Response.AppendHeader("Content-Disposition",
                "attachment;filename=" + fileName);

            curContext.Response.BinaryWrite(Export(dt, heardList).GetBuffer());
            curContext.Response.End();
        }

        #region 定义单元格常用到样式的枚举
        public enum stylexls
        {
            头,
            url,
            时间,
            数字,
            钱,
            百分比,
            中文大写,
            科学计数法,
            默认
        }
        #endregion

        #region 定义单元格常用到样式
        private static ICellStyle Getcellstyle(IWorkbook wb, stylexls str)
        {
            ICellStyle cellStyle = wb.CreateCellStyle();

            //定义几种字体
            //也可以一种字体，写一些公共属性，然后在下面需要时加特殊的
            IFont font12 = wb.CreateFont();
            font12.FontHeightInPoints = ;
            font12.FontName = "微软雅黑";

            IFont headerFont = wb.CreateFont();
            headerFont.FontHeightInPoints = ;
            headerFont.IsBold = true;
            headerFont.FontName = "微软雅黑";

            IFont font = wb.CreateFont();
            font.FontName = "微软雅黑";
            //font.Underline = 1;下划线  

            IFont fontcolorblue = wb.CreateFont();
            fontcolorblue.Color = HSSFColor.OliveGreen.Blue.Index;
            fontcolorblue.IsItalic = true;//下划线
            fontcolorblue.FontName = "微软雅黑";

            //边框
            cellStyle.BorderBottom = NPOI.SS.UserModel.BorderStyle.Dotted;
            cellStyle.BorderLeft = NPOI.SS.UserModel.BorderStyle.Hair;
            cellStyle.BorderRight = NPOI.SS.UserModel.BorderStyle.Hair;
            cellStyle.BorderTop = NPOI.SS.UserModel.BorderStyle.Dotted;
            //边框颜色
            cellStyle.BottomBorderColor = HSSFColor.OliveGreen.Blue.Index;
            cellStyle.TopBorderColor = HSSFColor.OliveGreen.Blue.Index;

            //背景图形，我没有用到过。感觉很丑
            //cellStyle.FillBackgroundColor = HSSFColor.OLIVE_GREEN.BLUE.index;
            //cellStyle.FillForegroundColor = HSSFColor.OLIVE_GREEN.BLUE.index;
            cellStyle.FillForegroundColor = HSSFColor.White.Index;
            // cellStyle.FillPattern = FillPatternType.NO_FILL;
            cellStyle.FillBackgroundColor = HSSFColor.Blue.Index;

            //水平对齐
            cellStyle.Alignment = NPOI.SS.UserModel.HorizontalAlignment.Left;

            //垂直对齐
            cellStyle.VerticalAlignment = VerticalAlignment.Center;

            //自动换行
            cellStyle.WrapText = true;

            //缩进;当设置为1时，前面留的空白太大了。希旺官网改进。或者是我设置的不对
            cellStyle.Indention = ;

            //上面基本都是设共公的设置
            //下面列出了常用的字段类型
            switch (str)
            {
                case stylexls.头:
                    cellStyle.Alignment = NPOI.SS.UserModel.HorizontalAlignment.Center;
                    // cellStyle.FillPattern = FillPatternType.LEAST_DOTS;
                    cellStyle.SetFont(headerFont);
                    break;
                case stylexls.时间:
                    IDataFormat datastyle = wb.CreateDataFormat();

                    cellStyle.DataFormat = datastyle.GetFormat("yyyy-MM-dd HH:mm:ss");
                    cellStyle.SetFont(font);
                    break;
                case stylexls.数字:
                    cellStyle.DataFormat = HSSFDataFormat.GetBuiltinFormat("0.00");
                    cellStyle.SetFont(font);
                    break;
                case stylexls.钱:
                    IDataFormat format = wb.CreateDataFormat();
                    cellStyle.DataFormat = format.GetFormat("￥#,##0");
                    cellStyle.SetFont(font);
                    break;
                case stylexls.url:
                    fontcolorblue.Underline = FontUnderlineType.Single;
                    cellStyle.SetFont(fontcolorblue);
                    break;
                case stylexls.百分比:
                    cellStyle.DataFormat = HSSFDataFormat.GetBuiltinFormat("0.00%");
                    cellStyle.SetFont(font);
                    break;
                case stylexls.中文大写:
                    IDataFormat format1 = wb.CreateDataFormat();
                    cellStyle.DataFormat = format1.GetFormat("[DbNum2][$-804]0");
                    cellStyle.SetFont(font);
                    break;
                case stylexls.科学计数法:
                    cellStyle.DataFormat = HSSFDataFormat.GetBuiltinFormat("0.00E+00");
                    cellStyle.SetFont(font);
                    break;
                case stylexls.默认:
                    cellStyle.SetFont(font);
                    break;
            }
            return cellStyle;

        }

        #endregion
    }