inlineformset_factory modify page throwing errors

Question

My problem:

MultiValueDictKeyError at /classroom-update/1
"u'student_set-0-id'"

My view:

@login_required
def classroom_update(request, pk):

    classroom = get_object_or_404(Classroom, pk=pk)
    students = classroom.student_set.all()

    StudentFormSet = inlineformset_factory(Classroom, Student,form=StudentForm, can_delete=False, extra=0)

    if request.method == 'POST':

        classroom_form = ClassroomForm(request.POST)
        student_formset = StudentFormSet(request.POST)

        if classroom_form.is_valid() and student_formset.is_valid():
            classroom = classroom_form.save(commit=False)
            classroom.user = request.user
            classroom.save()
            for form in student_formset.forms:
                student = form.save(commit=False)
                student.classroom = classroom
                student.save()
            return HttpResponseRedirect('/') # Redirect to a 'success' page
    else:
        classroom_form = ClassroomForm(instance=classroom)
        student_formset = StudentFormSet(instance=classroom)

    # For CSRF protection
    # See http://docs.djangoproject.com/en/dev/ref/contrib/csrf/ 
    c = {'classroom_form': classroom_form,
         'student_formset': student_formset,
        }
    c.update(csrf(request))

    return render_to_response('reports/modify_classroom.html', c)

...and my template code

{% extends 'reports/base.html' %}
{% load crispy_forms_tags %}

{% block head %}
  <title>Early Screening Project</title>

{% endblock %}

{% block content %}
<div class="row">
<div class='large-12 columns'>

    <form action="" method="POST">{% csrf_token %}
        <div class="section">
            {% crispy classroom_form %}
        </div>
        {{ student_formset.management_form|crispy }}
        {% for form in student_formset.forms %}
        <div class="item">
          {% crispy form %}
        </div>
        {% endfor %}
        <input type="submit" value="Submit" class='button' />
    </form>

</div>
</div>
{% endblock %}

Thanks for the help!

Answer 1

In Template:

{% for form in student_formset.forms %}
    {{ form.id }} #Here , you have to pass form id
    <div class="item">
        {% crispy form %}
    </div>
{% endfor %}

Check it : Django docs

Cheers

--- Update:
You also have to pass the management form

    {{ formset.management_form }}

--Response to comment:

I had the same error too , here is the fix:

classroom = get_object_or_404(Classroom, pk=pk)
#.....
if request.method == 'POST':

        classroom_form = ClassroomForm(request.POST , instance=classroom) 
        #This is an Update View , missing to add instance , will result a new entry.

        student_formset = StudentFormSet(request.POST, instance = classroom)
        #passing the instance here would solve the list index out of range

    if classroom_form.is_valid() and student_formset.is_valid():
        classroom = classroom_form.save(commit=False)
        classroom.user = request.user
        classroom.save()
        for form in student_formset.forms:
            student = form.save(commit=False)
            student.classroom = classroom
            student.save()
        return HttpResponseRedirect('/') # Redirect to a 'success' page