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90 | forms.py
========
from django.forms.formsets import Form, BaseFormSet, formset_factory, \
ValidationError
class QuestionForm(Form):
"""Form for a single question on a quiz"""
def __init__(self, *args, **kwargs):
# CODE TRICK #1
# pass in a question from the formset
# use the question to build the form
# pop removes from dict, so we don't pass to the parent
self.question = kwargs.pop('question')
super(QuestionForm, self).__init__(*args, **kwargs)
# CODE TRICK #2
# add a non-declared field to fields
# use an order_by clause if you care about order
self.answers = self.question.answer_set.all(
).order_by('id')
self.fields['answers'] = forms.ModelChoiceField(
queryset=self.answers())
class BaseQuizFormSet(BaseFormSet):
def __init__(self, *args, **kwargs):
# CODE TRICK #3 - same as #1:
# pass in a valid quiz object from the view
# pop removes arg, so we don't pass to the parent
self.quiz = kwargs.pop('quiz')
# CODE TRICK #4
# set length of extras based on query
# each question will fill one 'extra' slot
# use an order_by clause if you care about order
self.questions = self.quiz.question_set.all().order_by('id')
self.extra = len(self.questions)
if not self.extra:
raise Http404('Badly configured quiz has no questions.')
# call the parent constructor to finish __init__
super(BaseQuizFormSet, self).__init__(*args, **kwargs)
def _construct_form(self, index, **kwargs):
# CODE TRICK #5
# know that _construct_form is where forms get added
# we can take advantage of this fact to add our forms
# add custom kwargs, using the index to retrieve a question
# kwargs will be passed to our form class
kwargs['question'] = self.questions[index]
return super(BaseQuizFormSet, self)._construct_form(index, **kwargs)
QuizFormSet = formset_factory(
QuestionForm, formset=BaseQuizDynamicFormSet)
views.py
========
from django.http import Http404
def quiz_form(request, quiz_id):
try:
quiz = Quiz.objects.get(pk=quiz_id)
except Quiz.DoesNotExist:
return Http404('Invalid quiz id.')
if request.method == 'POST':
formset = QuizFormSet(quiz=quiz, data=request.POST)
answers = []
if formset.is_valid():
for form in formset.forms:
answers.append(str(int(form.is_correct())))
return HttpResponseRedirect('%s?a=%s'
% (reverse('result-display',args=[quiz_id]), ''.join(answers)))
else:
formset = QuizFormSet(quiz=quiz)
return render_to_response('quiz.html', locals())
template
========
Just change this:
{% for form in forms %}
to this:
{% for form in formset.forms %}
|
Comments
This snippet has made my evening. I've been crawling the search engines, #django IRC, etc. and no one was able to help at all (god bless 'em for trying).
Thanks to anyone and everyone who contributed, especially you smagala. I used this to create a set of formsets so that we had a voting system on our site where you have categories that have questions that have choices that are either something the user chooses from a drop-down or "nominates" by using an empty text box next to the question they'd like to nominate a choice for.
It's always easy to do things in Django once you learn how, but sometimes finding the how takes a few days... :D
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