protected void btn_Click(object sender, EventArgs e)
    {
        try
        {
            DataSet DsSub = new DataSet();
            string JourneyDate = txtDate.Text.ToString();
            BitlaAPI objbitla = new BitlaAPI();
            IBitlaAPILayer objBitlaAPILayer = null;
            objBitlaAPILayer = new BitlaAPILayer();
            objBitlaAPILayer.URL = BitlaConstants.URL;
            objBitlaAPILayer.ApiKey = BitlaConstants.API_KEY;
            objBitlaAPILayer.Date = JourneyDate;
            DataSet dsBitlaAllAvailableRoutes = null;

            dsBitlaAllAvailableRoutes = objbitla.GetAllAvailableRoutes(objBitlaAPILayer.URL,objBitlaAPILayer.ApiKey, objBitlaAPILayer.Date);
            dsBitlaAllAvailableRoutes.WriteXml(Server.MapPath("~/Routes/" + JourneyDate + ".xml"));
            lblMsg.Text = " Submitted. ";
            XmlDataDocument XmlDocRef = new XmlDataDocument();
            // StreamWriter XmlDataRef = new StreamWriter(Path.Combine(HttpRuntime.AppDomainAppPath, "App_Data\\XMLfiles\\" + "RefCallback.xml"), false);
            XmlDocRef.Load(Path.Combine(HttpRuntime.AppDomainAppPath, "App_Data\\XMLfiles\\" + "RefCallback.xml"));
            foreach (DataRow row in dsBitlaAllAvailableRoutes.Tables[1].Rows)
            {
                string DirectoryPath = Server.MapPath("~/App_Data/XMLfiles");
                DirectoryInfo dir = new DirectoryInfo(DirectoryPath);
                if (!dir.Exists)
                {
                    dir.Create();
                }
                string filepath = "~/App_Data/XMLfiles/" + "RefCallback.xml";
                string DirectoryPath1 = Server.MapPath(filepath);
                DirectoryInfo dir1 = new DirectoryInfo(DirectoryPath1);

                if (dir1.Exists == true)
                {
                    DataSet ds1 = new DataSet();
                    DataTable dt = new DataTable("Refcal");
                    dt.Columns.Add("Date");
                    dt.Columns.Add("id");
                    dt.Columns.Add("travel_id");
                    dt.Columns.Add("reservation_id");
                    DataRow dr1;
                    dr1 = dt.NewRow();
                    dr1["Date"] = JourneyDate;
                    dr1["id"] = row["reservation_id"];
                    dr1["travel_id"] = row["travel_id"];
                    dr1["reservation_id"] = row["reservation_id"];
                    dt.Rows.Add(dr1);
                    ds1.Tables.Add(dt);
                    ds1.EnforceConstraints = false;
                    XmlDataDocument XmlDoc = new XmlDataDocument(ds1);
                    // Write down the XML declaration
                    // XmlDeclaration xmlDeclaration = XmlDoc.CreateXmlDeclaration("1.0", "utf-8", null);
                    // Create the root element
                    //XmlElement rootNode = XmlDoc.CreateElement("CallBack");
                    //XmlDoc.InsertBefore(xmlDeclaration, XmlDoc.DocumentElement);
                   // XmlDoc.AppendChild(rootNode);
                    XmlDoc.Save(Server.MapPath(filepath));

                }
                else
                {
                    //create node and add value
                    XmlNode node = XmlDocRef.CreateNode(XmlNodeType.Element, "Refcal", null);
                    node.InnerXml = "<Date>" + JourneyDate + "</Date><id>" + row["id"] + "</id><travel_id>" + row["travel_id"] + "</travel_id><reservation_id>" + row["reservation_id"] + "</reservation_id>";
                    //add to elements collection
                    XmlDocRef.DocumentElement.AppendChild(node);
                    //DsSub.ReadXml(Server.MapPath("~/App_Data/XMLfiles/" + "RefCallback.xml"));
                    //DataRow dr;
                    //dr = DsSub.Tables[0].NewRow();
                    //dr["Date"] = JourneyDate;
                    //dr["id"] = row["id"];
                    //dr["travel_id"] = row["travel_id"];
                    //dr["reservation_id"] = row["reservation_id"];
                    //DsSub.Tables[0].Rows.Add(dr);
                }

            }
            XmlDocRef.Save(Path.Combine(HttpRuntime.AppDomainAppPath, "App_Data\\XMLfiles\\" + "RefCallback.xml"));
            //DataSet ds2 = new DataSet();
            //ds2.EnforceConstraints = false;
            //XmlDataDocument XmlDoc1 = new XmlDataDocument(ds2);
            //StreamWriter XmlData1 = new StreamWriter(Server.MapPath("~/App_Data/XMLfiles/" + "RefCallback.xml"), false);
            //DsSub.WriteXml(XmlData1);
            //XmlData1.Close();

        }
        catch (Exception)
        {
           // throw;
        }
    }