private void Login()
        {
            if (string.IsNullOrWhiteSpace(UserName) || string.IsNullOrWhiteSpace(Password))
            {
                PageService.DisplayAlert("Alert", "Enter all Values", "Ok");
                return;
            }

            var customer = Reader.GetCustomerFromUserId(UserName, Password);

            if (customer != null)
            {
                PageService.PushAsync(new OrderPage(customer));
            }
            else
            {
                PageService.DisplayAlert("Error", "Invalid User", "Ok");
            }
        }