public void ToExcel(DataTable dt)
    {
        #region 3s  
        var FilePath = @"D:\ToExcel\";//产生Excel文件路径
        DeleteFile(FilePath);
        //创建全新的Workbook 
        var workbook = new HSSFWorkbook();//一個sheet最多65536行
        var count = 0;
        for (double i = 0; i < Convert.ToDouble(dt.Rows.Count) / Convert.ToDouble(65534); i++)//每个Excel文件的一个页签只能存放65536行数据
        {
            var row_index = 0;
            //创建Sheet
            workbook.CreateSheet("Sheet" + i);
            //根据Sheet名字获得Sheet对象  
            var sheet = workbook.GetSheet("Sheet" + i);
            IRow row;
            row = sheet.CreateRow(row_index);

            //写入标题
            for (int j = 0; j < dt.Columns.Count; j++)
            {
                row.CreateCell(j).SetCellValue(dt.Columns[j].Caption.ToString());
            }
            row = sheet.CreateRow(++row_index);

            //写入数据
            for (int j = 0; j < (dt.Rows.Count - count > 65534 ? 65534 : dt.Rows.Count - count); j++)
            {
                var r = dt.Rows[j + count];
                for (int k = 0; k <dt.Columns.Count; k++)
                {
                    row.CreateCell(k).SetCellValue(r[k].ToString());

                    //如果是数字,判断是否需要转换为数字
                    //if (IsNumeric(r[k].ToString()))
                    //{
                    //    row.CreateCell(k).SetCellValue(Convert.ToDouble(r[k].ToString()));
                    //}
                    //else
                    //{
                    //    row.CreateCell(k).SetCellValue(r[k].ToString());
                    //}
                }

                row = sheet.CreateRow(++row_index);
            }
            count += row_index - 2;
        }
        //保存Workbook方式一： 以文件形式保存到服务器中（每次导出都会生成一个文件，慎重使用）
        var FileName = DateTime.Now.ToString("yyyyMMddHHmmss") + ".xls";

        var sw = File.Create(FilePath + FileName);
        workbook.Write(sw);
        sw.Close();
        var EC = new ExcelConverter();
        EC.WebopenExcel(Response, FilePath + FileName);
        #endregion
    }