Thymeleaf + Springboot + Bootstrap - Checkbox

[eventoul]

Hi!

I have an issue with the code below:

`

                        <tr th:each="course : ${department.courses}">

                            <th th:text="${course.id}"></th>
                            <th th:text="${course.title}"></th>
                            <th th:text="${course.mandatory}"></th>
                            <th th:text="${course.duration}"></th>
                            <th th:text="${course.credits}"></th>
                            <th>
                                <div class="form-check">
                                    <label class="form-check-label" for="checkboxCourses"></label>
                                    <input id="checkboxCourses"  type="checkbox"
                                           class="form-check-input"
                                           th:value="${course.id}"
                                           th:field="*{courses}"
                                           th:checked="${course.mandatory}"
                                    />
                                </div>
                            </th>
                        </tr>
                    </tbody>`

I want the checkbox to be checked when a course is mandatory.

The th:field="*{courses}" refers to a Student model, which has a many-to-many relationship with the Course model.

I noticed that the th:checked="${course.mandatory}" works when I didn't have the th:field, but then I can't bind the course.id to save it in DB.

Any ideas?

PS: I want to be checked and disabled.

[LalithK90]

yap @eventoul

I have the same issue but I manage it using the following

<input id="checkboxCourses"  
		type="checkbox" 
		class="form-check-input" 
		th:value="${course.id}" 
		name="courses"                
		th:checked="${course.mandatory}"
          />

There is an assumption that course.mandatory variable value is "selected"

[danielfernandez]

This is not a bug — it's the expected behaviour of th:field on checkboxes.

When th:field="*{courses}" is applied to a checkbox, Thymeleaf controls the checked attribute itself: it renders the checkbox as checked if and only if the bound collection (courses) contains the checkbox's value. Any th:checked on the same element is overridden. The th:checked attribute is meant to be used in non-form-binding scenarios.