Form value is null with Thymeleaf and Spring MVC

Question

I'm trying to process a form with Thymeleaf and Spring MVC. The user should select a reservation, which is then saved in the Form.

The Template looks like this:

<form action="#" th:object="${reservationselectionform}">

                <select th:field="*{reservationSelection}" class="selectpicker" data-live-search="true" style="display: none;" >
                    <option th:each="reservation : ${reservationlist}"
                            th:value="${reservation}"
                            th:text="${reservation.user.userAccount.firstname}">Tyler Durden</option>
                </select>
<button type="submit" class="btn btn-primary" formaction="/checkintest" formmethod="post">Weiter</button>

I want to save the reservation object to work with it in another view (checkin_test). This doesn't work, as the reservation object is always null.

The controller looks like this:

@RequestMapping(value="choose_reservation", method = RequestMethod.GET)
    public String chose_reservation(ModelMap modelMap{

       modelMap.addAttribute("reservationselectionform", new ReservationSelectionForm());
       return "checkin/choose_reservation";

    }
@RequestMapping("/checkintest")
public String personaldata (ModelMap modelMap,
                                @ModelAttribute("reservationselectionform") ReservationSelectionForm reservationSelectionForm){

       return "checkin/checkintest";
    }

The form is as simple as:

public class ReservationSelectionForm {

private Reservation reservationSelection;

@NotEmpty
private String firstname;

@NotEmpty
private String lastname;

//getter & setter

If I try setting the firstname using the form, the firstname is included in the ReservationSelectionForm perfectly fine.

When I pass the whole Reservation object (th:value="${reservation}") , it is always null in the ReservationSelectionForm.

Can someone explain this to me and/or help me to pass the whole reservation object?

Answer 1

Your select list is always empty.
<option th:each="reservation : ${reservationlist}"
reservationlist is never added to model so th:each is iterating null