C# NPOI生成Excel文档（简单样式）

效果图：

代码： 

/// <summary>
        /// 导出Excel
        /// </summary>
        /// <param name="DeptId"></param>
        [HttpPost]
        public void ExportToExcel(int DeptId,List<FM_CostApply> CostApplyList, int beginYear, int beginMonth, int endYear, int endMonth)
        { 
            foreach (var Item in CostApplyList)
            {
                CostApplyItem.AddRange(Item.FM_CostApplyItem);
            }
            var Project = CostApplyItem.GroupBy(a => a.FM_Project.ProjectName).ToList();
            //创建工作簿
            HSSFWorkbook hssfworkbook = new HSSFWorkbook();
            string[] headName = { "年度", "月", "日", "申请类型", "新科目名称", "部门名称", "项目名称", "凭证号", "摘要", "金额" };
            string[] ColumnName = { "Year", "Month", "Day", "Type", "SubJectName", "DeptName", "ProjectName", "CardNum", "Summary", "Cost" };
            //创建Sheet页
            if (Project.Count > 0)
            {
                foreach (var proc in Project)
                {
                    //该项目下申请的所有的科目
                    var SubjectName = CostApplyItem.Where(a => a.FM_Project.ProjectName == proc.Key).GroupBy(a => a.FM_SecondSubject.SubjectName).ToList();
                    try
                    {
                        //创建Sheet页
                        ISheet sheet = hssfworkbook.CreateSheet(proc.Key);

                        //获取项目下的费用明细
                        List<CostApplyExcel> model = GetCostApply(proc.Key, CostApplyList);

                        var Dic = model.GroupBy(a => a.SubJectName).ToDictionary(w => w.Key, r => r.ToList());

                        //集合转换为DataTable
                        DataTable dt = ConvtToDataTable.ToDataTable<CostApplyExcel>(model);

                        int RowIndex = 2;

                        #region  如果为第一行
                        IRow IRow = sheet.CreateRow(0);
                        for (int h = 0; h < 10; h++)
                        {
                            ICell Icell = IRow.CreateCell(h);
                            Icell.SetCellValue(BeginDate.ToString("yyyy.MM") + "-" + EndDate.ToString("yyyy.MM") + " " + proc.Key + "项目汇总表");

                            ICellStyle style = hssfworkbook.CreateCellStyle();
                            //设置单元格的样式：水平对齐居中
                            style.Alignment = HorizontalAlignment.CENTER;
                            //新建一个字体样式对象
                            IFont font = hssfworkbook.CreateFont();
                            font.FontName = "宋体";
                            font.FontHeightInPoints = 18;
                            //设置字体加粗样式
                            font.Boldweight = (short)FontBoldWeight.BOLD;
                            //使用SetFont方法将字体样式添加到单元格样式中 
                            style.SetFont(font);
                            //将新的样式赋给单元格
                            Icell.CellStyle = style;
                            //合并单元格
                            sheet.AddMergedRegion(new CellRangeAddress(0, 0, 0, 9));
                        }
                        #endregion

                        #region   表头
                        IRow Irows2 = sheet.CreateRow(1);
                        for (int j = 0; j < 10; j++)
                        {
                            ICell Icell2 = Irows2.CreateCell(j);
                            ICellStyle Istyle2 = hssfworkbook.CreateCellStyle();
                            //设置边框
                            Istyle2.BorderTop = BorderStyle.THIN;
                            Istyle2.BorderBottom = BorderStyle.THIN;
                            Istyle2.BorderLeft = BorderStyle.THIN;
                            Istyle2.BorderRight = BorderStyle.THIN;
                            //设置单元格的样式：水平对齐居中
                            Istyle2.Alignment = HorizontalAlignment.CENTER;
                            //新建一个字体样式对象
                            IFont Ifont2 = hssfworkbook.CreateFont();
                            Ifont2.FontName = "宋体";
                            Ifont2.FontHeightInPoints = 11;
                            //设置字体加粗样式
                            Ifont2.Boldweight = (short)FontBoldWeight.BOLD;
                            //使用SetFont方法将字体样式添加到单元格样式中 
                            Istyle2.SetFont(Ifont2);
                            //将新的样式赋给单元格
                            Icell2.CellStyle = Istyle2;
                            Icell2.SetCellValue(headName[j]);
                        }
                        #endregion

                        foreach (var DicItem in Dic)
                        {
                            int SumStartRows = RowIndex + 1;         //求和的开始行 
                            //集合转换为DataTable
                            DataTable table = ConvtToDataTable.ToDataTable<CostApplyExcel>(DicItem.Value);
                            for (int i = 0; i <= DicItem.Value.Count; i++)
                            {
                                IRow row = sheet.CreateRow(RowIndex);

                                if (i == DicItem.Value.Count)
                                {
                                    for (int j = 0; j < 10; j++)
                                    {
                                        if (j == 3)
                                        {
                                            #region      汇总求和文字
                                            ICell cell = row.CreateCell(j);

                                            DataRow TableRow = table.Rows[i - 1];
                                            string subName = TableRow[5].ToString();

                                            ICellStyle style = hssfworkbook.CreateCellStyle();
                                            //设置边框
                                            style.BorderTop = BorderStyle.THIN;
                                            style.BorderBottom = BorderStyle.THIN;
                                            style.BorderLeft = BorderStyle.THIN;
                                            style.BorderRight = BorderStyle.THIN;
                                            //设置单元格的样式：水平对齐居中
                                            style.Alignment = HorizontalAlignment.CENTER;
                                            //新建一个字体样式对象
                                            IFont font = hssfworkbook.CreateFont();
                                            font.FontName = "宋体";
                                            font.FontHeightInPoints = 11;
                                            //设置字体加粗样式
                                            font.Boldweight = (short)FontBoldWeight.BOLD;
                                            //使用SetFont方法将字体样式添加到单元格样式中 
                                            style.SetFont(font);
                                            //将新的样式赋给单元格
                                            cell.CellStyle = style;
                                            cell.SetCellValue(subName + " 汇总");
                                            #endregion
                                        }
                                        else if (j == 9)            //合计
                                        {
                                            #region      汇总求和公式插入
                                            ICell cell = row.CreateCell(j);
                                            ICellStyle style = hssfworkbook.CreateCellStyle();
                                            //设置边框
                                            style.BorderTop = BorderStyle.THIN;
                                            style.BorderBottom = BorderStyle.THIN;
                                            style.BorderLeft = BorderStyle.THIN;
                                            style.BorderRight = BorderStyle.THIN;
                                            //设置单元格的样式：水平对齐居中
                                            style.Alignment = HorizontalAlignment.CENTER;
                                            //新建一个字体样式对象
                                            IFont font = hssfworkbook.CreateFont();
                                            font.FontName = "宋体";
                                            font.FontHeightInPoints = 11;
                                            //使用SetFont方法将字体样式添加到单元格样式中 
                                            style.SetFont(font);
                                            //将新的样式赋给单元格
                                            cell.CellStyle = style;

                                            string format = "sum(";
                                            for (int s = SumStartRows; s < (DicItem.Value.Count + SumStartRows); s++)
                                            {
                                                format += ("J" + s + ",");
                                            }
                                            format += ")";

                                            cell.SetCellFormula(format);

                                            #endregion      汇总求和
                                        }
                                        else
                                        {
                                            #region      汇总求和-普通单元格
                                            ICell cell = row.CreateCell(j);
                                            ICellStyle style = hssfworkbook.CreateCellStyle();
                                            //设置边框
                                            style.BorderTop = BorderStyle.THIN;
                                            style.BorderBottom = BorderStyle.THIN;
                                            style.BorderLeft = BorderStyle.THIN;
                                            style.BorderRight = BorderStyle.THIN;
                                            //设置单元格的样式：水平对齐居中
                                            style.Alignment = HorizontalAlignment.CENTER;
                                            //新建一个字体样式对象
                                            IFont font = hssfworkbook.CreateFont();
                                            font.FontName = "宋体";
                                            font.FontHeightInPoints = 11;
                                            //使用SetFont方法将字体样式添加到单元格样式中 
                                            style.SetFont(font);
                                            //将新的样式赋给单元格
                                            cell.CellStyle = style;
                                            #endregion
                                        }
                                    }
                                }
                                else if (i < DicItem.Value.Count)
                                {
                                    #region   插入值
                                    DataRow TableRow = table.Rows[i];
                                    for (int j = 0; j < 10; j++)
                                    {
                                        ICell cell = row.CreateCell(j);
                                        ICellStyle style = hssfworkbook.CreateCellStyle();
                                        //设置边框
                                        style.BorderTop = BorderStyle.THIN;
                                        style.BorderBottom = BorderStyle.THIN;
                                        style.BorderLeft = BorderStyle.THIN;
                                        style.BorderRight = BorderStyle.THIN;
                                        //设置单元格的样式：水平对齐居中
                                        style.Alignment = HorizontalAlignment.CENTER;
                                        //设置单元格属性为文本
                                        style.DataFormat = HSSFDataFormat.GetBuiltinFormat("@");
                                        //新建一个字体样式对象
                                        IFont font = hssfworkbook.CreateFont();
                                        font.FontName = "宋体";
                                        font.FontHeightInPoints = 11;
                                        //使用SetFont方法将字体样式添加到单元格样式中 
                                        style.SetFont(font);
                                        //将新的样式赋给单元格
                                        cell.CellStyle = style;
                                        string val = TableRow[ColumnName[j]].ToString();
                                        if (j == 9)
                                        {
                                            double cost = double.Parse(val);
                                            cell.SetCellValue(cost);
                                        }
                                        else
                                        {
                                            cell.SetCellValue(val);
                                        }
                                    }
                                    #endregion
                                }
                                RowIndex++;
                            }
                        }
                        for (int h = 0; h < 9; h++)
                        {
                            sheet.AutoSizeColumn(h);　　//会按照值的长短 自动调节列的大小
                        }
                    }
                    catch (Exception ex) { }
                }
            }
            else
            {
                //创建Sheet页
                ISheet sheet = hssfworkbook.CreateSheet();
            }
            string Path = Server.MapPath("~/upload/财务导出");
            if (!System.IO.Directory.Exists(Path))
                System.IO.Directory.CreateDirectory(Path);
            string fileName = DateTime.Now.ToFileTime() + ".xls";
            using (FileStream file = new FileStream(Path + "\" + fileName, FileMode.Create))
            {
                hssfworkbook.Write(file);　　//创建test.xls文件。
                file.Close();
                result = ConfigurationManager.AppSettings["Websitet"] + "upload/财务导出/" + fileName;
            }
            HttpContext context = System.Web.HttpContext.Current;
            context.Response.Write(result);
            context.Response.End();
        }