DataTable导出Excel

                    string fileName = "出勤明细" + DateTime.Now.ToString("yyyyMMdd");
                    //导出成Excel
                    var Result = officeHp.DtToExcel(attendDt, "XXX", new string[] { "序号", "班级名称", "学生姓名", "学生学号", "手机号", "签到时间" }, "考勤明细", fileName);

/// <summary>
        /// DataTable 导出到 Excel
        /// </summary>
        /// <param name="dt">数据表</param>
        /// <param name="captions">要导出的列标题</param>
        /// <param name="fieldNames">要导出的列名</param>
        /// <param name="sheetName">工作簿名称</param>
        public string DtToExcel(DataTable dt, string captions, string[] fieldNames, string sheetName, string fileName)
        {
            //第一步判断给出标题和查出来的数据是否相同
            if (dt.Columns.Count != fieldNames.Length) { return "ERROR"; }

            Workbook workbook = new Workbook(); //工作簿 

            Worksheet sheet = workbook.Worksheets[0]; //工作表
            sheet.Name = sheetName;    //设置工作表的名称
            Cells cells = sheet.Cells;//单元格
            //为标题设置样式
            Style styleTitle = workbook.Styles[workbook.Styles.Add()];//新增样式
            styleTitle.HorizontalAlignment = TextAlignmentType.Center;//文字居中
            styleTitle.Font.Name = "宋体";//文字字体
            styleTitle.Font.Size = 18;//文字大小
            styleTitle.Font.IsBold = true;//粗体 

            //样式2
            Style style2 = workbook.Styles[workbook.Styles.Add()];//新增样式
            style2.HorizontalAlignment = TextAlignmentType.Center;//文字居中
            style2.Font.Name = "宋体";//文字字体
            style2.Font.Size = 14;//文字大小
            style2.Font.IsBold = true;//粗体
            style2.IsTextWrapped = true;//单元格内容自动换行
            style2.Borders[BorderType.LeftBorder].LineStyle = CellBorderType.Thin;
            style2.Borders[BorderType.RightBorder].LineStyle = CellBorderType.Thin;
            style2.Borders[BorderType.TopBorder].LineStyle = CellBorderType.Thin;
            style2.Borders[BorderType.BottomBorder].LineStyle = CellBorderType.Thin;

            //样式3
            Style style3 = workbook.Styles[workbook.Styles.Add()];//新增样式
            style3.HorizontalAlignment = TextAlignmentType.Center;//文字居中
            style3.Font.Name = "宋体";//文字字体
            style3.Font.Size = 12;//文字大小
            style3.Borders[BorderType.LeftBorder].LineStyle = CellBorderType.Thin;
            style3.Borders[BorderType.RightBorder].LineStyle = CellBorderType.Thin;
            style3.Borders[BorderType.TopBorder].LineStyle = CellBorderType.Thin;
            style3.Borders[BorderType.BottomBorder].LineStyle = CellBorderType.Thin;

            int Colnum = dt.Columns.Count;//表格列数
            int Rownum = dt.Rows.Count;//表格行数 

            //生成行1 标题行
            cells.Merge(0, 0, 1, Colnum);//合并单元格
            cells[0, 0].PutValue(captions);//填写内容
            cells[0, 0].SetStyle(styleTitle);
            cells.SetRowHeight(0, 38);

            //生成行2 列名行
            for (int i = 0; i < Colnum; i++)
            {
                //cells[1, i].PutValue(dt.Columns[i].ColumnName);
                cells[1, i].PutValue(fieldNames[i]);
                cells[1, i].SetStyle(style2);
                cells.SetRowHeight(1, 25);
            }

            //生成数据行
            for (int i = 0; i < Rownum; i++)
            {
                for (int k = 0; k < Colnum; k++)
                {
                    cells[2 + i, k].PutValue(dt.Rows[i][k].ToString());
                    cells[2 + i, k].SetStyle(style3);
                }
                cells.SetRowHeight(2 + i, 24);
            }

            sheet.AutoFitColumns();     //设置单元格自适应
            workbook.Save(AppDomain.CurrentDomain.BaseDirectory + @"ExportFile\Excel\" + fileName + ".xlsx", SaveFormat.Auto);
            return "SUCCESS";
        }