django class-based views with inline model-form or formset

Question

I have the following models:

class Bill(models.Model):
    date = models.DateTimeField(_("Date of bill"),null=True,blank=True)

class Item(models.Model):
    name = models.CharField(_("Name"),max_length=100)
    price = models.FloatField(_("Price"))
    quantity = models.IntegerField(_("Quantity"))
    bill = models.ForeignKey("Bill",verbose_name=_("Bill"),
                             related_name="billitem")

I know that this is possible:

from django.forms.models import inlineformset_factory
inlineformset_factory(Bill, Item)

and then process this via standard view.

Now I was wondering, if there is a way to achieve the same (meaning: using a inline for adding/editing items belonging to a bill) using class based views (not for the admin-interface).

Answer 1

Key points is:

1. generated FormSets within forms.py using inlineformset_factory:

   BookImageFormSet = inlineformset_factory(BookForm, BookImage, extra=2)
   BookPageFormSet = inlineformset_factory(BookForm, BookPage, extra=5)
   

2. returned the FormSets within a CreateView class in views.py:

   def get_context_data(self, **kwargs):
       context = super(BookCreateView, self).get_context_data(**kwargs)
       if self.request.POST:
           context['bookimage_form'] = BookImageFormSet(self.request.POST)
           context['bookpage_form'] = BookPageFormSet(self.request.POST)
       else:
           context['bookimage_form'] = BookImageFormSet()
           context['bookpage_form'] = BookPageFormSet()
       return context
   

3. Used form_valid to save the form and formset:

    def form_valid(self, form):
        context = self.get_context_data()
        bookimage_form = context['bookimage_formset']
        bookpage_form = context['bookpage_formset']
        if bookimage_form.is_valid() and bookpage_form.is_valid():
            self.object = form.save()
            bookimage_form.instance = self.object
            bookimage_form.save()
            bookpage_form.instance = self.object
            bookpage_form.save()
            return HttpResponseRedirect('thanks/')
        else:
            return self.render_to_response(self.get_context_data(form=form))
   

Answer 2

I just added my own version after checking out some of those pre-made CBVs. I specifically needed control over multiple formsets -> one parent in a single view each with individual save functions.

I basically stuffed the FormSet data binding into a get_named_formsets function which is called by get_context_data and form_valid.

There, I check if all formsets are valid, and also look for a method that overrides a plain old formset.save() on a per formset basis for custom saving.

The template renders formsets via

{% with named_formsets.my_specific_formset as formset %}
 {{ formset }}
 {{ formset.management_form }}
{% endwith %}

I think I'll be using this system regularly.

class MyView(UpdateView): # FormView, CreateView, etc
    def get_context_data(self, **kwargs):
        ctx = super(MyView, self).get_context_data(**kwargs)
        ctx['named_formsets'] = self.get_named_formsets()
        return ctx

    def get_named_formsets(self):
        return {
            'followup': FollowUpFormSet(self.request.POST or None, prefix='followup'),
            'action': ActionFormSet(self.request.POST or None, prefix='action'),
        }

    def form_valid(self, form):
        named_formsets = self.get_named_formsets()
        if not all((x.is_valid() for x in named_formsets.values())):
            return self.render_to_response(self.get_context_data(form=form))

        self.object = form.save()

        # for every formset, attempt to find a specific formset save function
        # otherwise, just save.
        for name, formset in named_formsets.items():
            formset_save_func = getattr(self, 'formset_{0}_valid'.format(name), None)
            if formset_save_func is not None:
                formset_save_func(formset)
            else:
                formset.save()
        return http.HttpResponseRedirect('')

    def formset_followup_valid(self, formset):
        """
        Hook for custom formset saving.. useful if you have multiple formsets
        """
        followups = formset.save(commit=False) # self.save_formset(formset, contact)
        for followup in followups:
            followup.who = self.request.user
            followup.contact = self.object
            followup.save()

Answer 3

You should try out django-extra-views. Look for CreateWithInlinesView and UpdateWithInlinesView.

Answer 4

I made some modification to original solution to let formset.is_valid() to work:

    if self.request.POST:
        context['fs'] = MyInlineFS(self.request.POST, instance=self.object)
    else:
        context['fs'] = MyInlineFS(instance=self.object)

Answer 5

The code in Jordan's answer didn't work for me. I posted my own question about this, which I believe I've now solved. The first argument to inlineformset_factory should be Book, not BookForm.

Answer 6

I needed to make one more modification to Jordan's and Speq's view's get_context_data() in order to have formset.non_form_errors exist in the template context.

...
if self.request.POST:
    context['fs'] = MyInlineFS(self.request.POST, instance=self.object)
    context['fs'].full_clean()  # <-- new
else:
    context['fs'] = MyInlineFS(instance=self.object)
return context

Answer 7

I red the generic source code of the 1.3-beta-1 :

The code is absolutely not ready for List editing or there is some black magic here. But I think that it can be implemented quickly.

If you look at the django.view.generic.edit (that support detailed object editing) module how it use the django.view.generic.detail module.

I think that a django.view.generic.list_edit module can be implemented using django.view.generic.list and some part from django.view.generic.edit.