private void DownloadBidFile(DataSet dsExtractData, string filename, string delimit)
        {
            try
            {
                if (txtFromDate.SelectedDate != null)
                {
                    fromdate = DateTime.Parse(txtFromDate.SelectedDate.ToString());
                }
                if (txtToDate.SelectedDate != null)
                {
                    todate = DateTime.Parse(txtToDate.SelectedDate.ToString());
                }
                string dateFormat = "dd-mm-yyyy";

                dsExtractData = onlineOrderBackOfficeBo.GetBSECustomer(adviserVo.advisorId, fromdate, todate);
                dsExtractData.Tables[0].Columns.Remove("C_DematAcceptedOn");

                StreamWriter str = new StreamWriter(Server.MapPath(@"~/UploadFiles/" + filename), false, System.Text.Encoding.Default);

                string Columns = string.Empty;

                foreach (DataColumn column in dsExtractData.Tables[0].Columns)
                {
                    Columns += column.ColumnName + delimit;
                }



                // Headers  For different types


                DataColumn[] arrCols = new DataColumn[dsExtractData.Tables[0].Columns.Count];
                dsExtractData.Tables[0].Columns.CopyTo(arrCols, 0);
                foreach (DataRow datarow in dsExtractData.Tables[0].Rows)
                {
                    string row = string.Empty;
                    int    i   = 0;
                    foreach (object item in datarow.ItemArray)
                    {
                        if (arrCols[i].DataType.FullName == "System.DateTime")
                        {
                            string strDate = string.IsNullOrEmpty(item.ToString()) ? "" : DateTime.Parse(item.ToString()).ToString(dateFormat);
                            row += strDate + delimit;
                        }
                        else
                        {
                            row += item.ToString().Trim() + delimit;
                        }
                        i++;
                    }
                    str.WriteLine(row.Remove(row.Length - 1, 1));
                }
                str.Flush();
                str.Close();
                string myFileData;
                // File in
                myFileData = File.ReadAllText(Server.MapPath("~/UploadFiles/" + filename));
                // Remove last CR/LF
                // 1) Check that the file has CR/LF at the end
                if (myFileData.EndsWith(Environment.NewLine))
                {
                    //2) Remove CR/LF from the end and write back to file (new file)
                    //File.WriteAllText(@"D:\test_backup.csv", myFileData.TrimEnd(null)); // Removes ALL white spaces from the end!
                    File.WriteAllText(Server.MapPath("~/UploadFiles/" + filename), myFileData.TrimEnd(Environment.NewLine.ToCharArray())); // Removes ALL CR/LF from the end!
                }
                #region download notepad or text file.
                Response.ContentType = "Text/Plain";
                Response.AppendHeader("Content-Disposition", "attachment;filename=" + filename);
                string aaa = Server.MapPath("~/UploadFiles/" + filename);
                Response.TransmitFile(Server.MapPath("~/UploadFiles/" + filename));
                HttpContext.Current.ApplicationInstance.CompleteRequest();
                Response.End();
                #endregion
            }
            catch (Exception ex)
            {
            }
            //finally
            //{
            //    System.IO.File.Delete(Server.MapPath("~/UploadFiles/" + filename));
            //}
        }