Epplus DataTable一次性导出

        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[0];
#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
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 = 0; 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 = 18;
                        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[1, 1, 1, dt.Columns.Count].Style.Fill.PatternType = ExcelFillStyle.Solid;
                        sheet2.Cells[1, 1, 1, dt.Columns.Count].Style.Fill.BackgroundColor.SetColor(Color.LightGray);

                        sheet2.Cells[2, 1, 2, dt.Columns.Count].Style.Fill.PatternType = ExcelFillStyle.Solid;
                        sheet2.Cells[2, 1, 2, dt.Columns.Count].Style.Fill.BackgroundColor.SetColor(Color.LightGray);
                        sheet2.Cells[1, 1, dt.Rows.Count + 1, dt.Columns.Count].Style.HorizontalAlignment = OfficeOpenXml.Style.ExcelHorizontalAlignment.Center;
                        sheet2.Cells[1, 1, dt.Rows.Count + 1, dt.Columns.Count].Style.Border.Left.Style = ExcelBorderStyle.Thin;
                        sheet2.Cells[1, 1, dt.Rows.Count + 1, dt.Columns.Count].Style.Border.Right.Style = ExcelBorderStyle.Thin;
                        sheet2.Cells[1, 1, dt.Rows.Count + 1, dt.Columns.Count].Style.Border.Top.Style = ExcelBorderStyle.Thin;
                        sheet2.Cells[1, 1, dt.Rows.Count + 1, dt.Columns.Count].Style.Border.Bottom.Style = ExcelBorderStyle.Thin;
                        sheet2.Cells[1, 1, dt.Rows.Count + 1, 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, 0, data.Length);
            if (data.Length <= 0)
                data = new Byte[] { 13, 10 };
            steam.Close();
            File.Delete(tmpPath);

            if (context.Request.UserAgent.ToLower().IndexOf("firefox") > -1)
            {
                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();
        }

单行读取的我就不写了网上多得很。 在写就有多多此一举了，  新人要不断摸索啊，我可是踩了半个月的坑，一个人日日夜夜的研究，才搞出来Epplus的图表和现在的单元格内换行啊，痛苦的不行，所以不能让你们太幸福了  哈哈~~~~~~~~~~~~~~~~~~~~~~~~~~