public void Export()

        {

            string fileName = "";

            if (string.IsNullOrEmpty(fileName) == true)

            {

                fileName = DateTime.Now.ToString("yyyyMMdd");

            }

            string tmpPath = context.Server.MapPath("~/upfiles/") + "Template_" + DateTime.Now.Ticks + ".xlsx";

            FileInfo file = new FileInfo(tmpPath);

            //导出Excel

            FileStream fs = new FileStream(tmpPath, FileMode.CreateNew, FileAccess.ReadWrite);

            try

            {

                ExcelPackage package = new ExcelPackage(fs);

                DataSet ds = new DataSet();

                //接收最后结果

                string drResult = string.Empty;

                DataTable dt = pmt.GetMyTaskList().Tables[];
#region   这一块是因为公司有个需求 要在单元格内进行换行，有多少个\n就需要换多少行，如果没有这个需求的 就不用要这一段了。

                foreach (DataRow dr in dt.Rows) {

                    string [] st4=dr["approvalInfo"].ToString().Split(new string[] { "\\n" },  StringSplitOptions.None);

                    for(int i = ; i < st4.Length; i++)

                    {

                        drResult += st4[i] + "   " + System.Environment.NewLine; //换行的关键字，这一句掉了 就没什么卵用了，为了这个换行，我差点没被逼死，这次就留着，我不想下次又找不到了。

                    }

                    dr["approvalInfo"] = drResult;

                    drResult = "";

                }
#endregion

                        #region

                        ExcelWorksheet sheet2 = package.Workbook.Worksheets.Add("sheet1");

                        sheet2.DefaultColWidth = ;

                        sheet2.Cells.Style.Font.Name = "宋体";

                        sheet2.Cells.Style.Numberformat.Format = "@";

                        sheet2.Cells.Style.WrapText = true;

                        sheet2.Cells["A1"].LoadFromDataTable(dt, true);

                        ///设置边框

                        sheet2.Cells[, , , dt.Columns.Count].Style.Fill.PatternType = ExcelFillStyle.Solid;

                        sheet2.Cells[, , , dt.Columns.Count].Style.Fill.BackgroundColor.SetColor(Color.LightGray);

                        sheet2.Cells[, , , dt.Columns.Count].Style.Fill.PatternType = ExcelFillStyle.Solid;

                        sheet2.Cells[, , , dt.Columns.Count].Style.Fill.BackgroundColor.SetColor(Color.LightGray);

                        sheet2.Cells[, , dt.Rows.Count + , dt.Columns.Count].Style.HorizontalAlignment = OfficeOpenXml.Style.ExcelHorizontalAlignment.Center;

                        sheet2.Cells[, , dt.Rows.Count + , dt.Columns.Count].Style.Border.Left.Style = ExcelBorderStyle.Thin;

                        sheet2.Cells[, , dt.Rows.Count + , dt.Columns.Count].Style.Border.Right.Style = ExcelBorderStyle.Thin;

                        sheet2.Cells[, , dt.Rows.Count + , dt.Columns.Count].Style.Border.Top.Style = ExcelBorderStyle.Thin;

                        sheet2.Cells[, , dt.Rows.Count + , dt.Columns.Count].Style.Border.Bottom.Style = ExcelBorderStyle.Thin;

                        sheet2.Cells[, , dt.Rows.Count + , dt.Columns.Count].Style.ShrinkToFit = true;//自适应宽度

                        #endregion

                package.Save();

            }

            catch (Exception ex)

            {

                Logger.Log.Error("导出Excel错误：" + ex.ToString());

            }

            finally

            {

                fs.Close();

            }

            byte[] data = null;

            FileStream steam = File.Open(tmpPath, FileMode.Open, FileAccess.Read);

            data = new byte[steam.Length];

            int result = steam.Read(data, , data.Length);

            if (data.Length <= )

                data = new Byte[] { ,  };

            steam.Close();

            File.Delete(tmpPath);

            if (context.Request.UserAgent.ToLower().IndexOf("firefox") > -)

            {

                HttpContext.Current.Response.AddHeader("Content-Disposition",

                                           "attachment;  filename*=\"" +

                                           HttpUtility.UrlEncode(fileName + ".xlsx") + "\"");

            }

            else

            {

                HttpContext.Current.Response.AddHeader("Content-Disposition",

                                           "inline;  filename=" +

                                           HttpUtility.UrlEncode(fileName + ".xlsx", System.Text.Encoding.UTF8));

            }

            HttpContext.Current.Response.AddHeader("Content-Length", data.Length.ToString());

            HttpContext.Current.Response.ContentType = "application/octet-stream";

            HttpContext.Current.Response.BinaryWrite(data);

            HttpContext.Current.Response.Flush();

            HttpContext.Current.ApplicationInstance.CompleteRequest();

        }