private void Application_Exit(object sender, ExitEventArgs e) { //My_Storage.WriteXml(App._students, "Students.xml"); //var dishes = new ObservableCollection<Menu> { new Menu { id = 0, menuName = "a", category= "abc", price= 3.99F }, new Menu { id = 0, menuName = "a", category = "abc", price= 3.99F }, // new Menu { id = 0, menuName = "a", category= "abc", price= 3.99F }, }; //var orders = new ObservableCollection<Orders> { new Orders { order_id = 0 ,id = 0, date = "12/02/2021", items = "Chicken Tikka", quantity = 1, amount= 17.99F, billing_status= "abc", action= "0" }, // new Orders { order_id = 0 ,id = 0, date = "12/02/2021", items = "Chicken Tikka", quantity = 1, amount= 17.99F, billing_status= "abc", action= "0" }, // new Orders { order_id = 0 ,id = 0, date = "12/02/2021", items = "Chicken Tikka", quantity = 1, amount= 17.99F, billing_status= "abc", action= "0" } }; My_Storage.WriteXml(App._order, "OrderList.xml"); //My_Storage.WriteXml(orders, "OrderList.xml"); My_Storage.WriteXml(App._menu, "MenuList.xml"); }