[Django]-Multiple Models in a single django ModelForm?

You can try to use this pieces of code:

class CombinedFormBase(forms.Form):
    form_classes = []

    def __init__(self, *args, **kwargs):
        super(CombinedFormBase, self).__init__(*args, **kwargs)
        for f in self.form_classes:
            name = f.__name__.lower()
            setattr(self, name, f(*args, **kwargs))
            form = getattr(self, name)
            self.fields.update(form.fields)
            self.initial.update(form.initial)

    def is_valid(self):
        isValid = True
        for f in self.form_classes:
            name = f.__name__.lower()
            form = getattr(self, name)
            if not form.is_valid():
                isValid = False
        # is_valid will trigger clean method
        # so it should be called after all other forms is_valid are called
        # otherwise clean_data will be empty
        if not super(CombinedFormBase, self).is_valid() :
            isValid = False
        for f in self.form_classes:
            name = f.__name__.lower()
            form = getattr(self, name)
            self.errors.update(form.errors)
        return isValid

    def clean(self):
        cleaned_data = super(CombinedFormBase, self).clean()
        for f in self.form_classes:
            name = f.__name__.lower()
            form = getattr(self, name)
            cleaned_data.update(form.cleaned_data)
        return cleaned_data

Example Usage:

class ConsumerRegistrationForm(CombinedFormBase):
    form_classes = [RegistrationForm, ConsumerProfileForm]

class RegisterView(FormView):
    template_name = "register.html"
    form_class = ConsumerRegistrationForm

    def form_valid(self, form):
        # some actions...
        return redirect(self.get_success_url())

I used django betterforms‘s MultiForm and MultiModelForm in my project. The code can be improved, though. For example, it’s dependent on django.six, which isn’t supported by 3.+, but all of these can easily be fixed

This question has appeared several times in StackOverflow, so I think it’s time to find a standardized way of coping with this.

erikbwork and me both had the problem that one can only include one model into a generic Class Based View. I found a similar way of approaching it like Miao, but more modular.

I wrote a Mixin so you can use all generic Class Based Views. Define model, fields and now also child_model and child_field – and then you can wrap fields of both models in a tag like Zach describes.

class ChildModelFormMixin: 
    ''' extends ModelFormMixin with the ability to include ChildModelForm '''
    child_model = ""
    child_fields = ()
    child_form_class = None

    def get_child_model(self):
        return self.child_model

    def get_child_fields(self):
        return self.child_fields

    def get_child_form(self):
        if not self.child_form_class:
            self.child_form_class = model_forms.modelform_factory(self.get_child_model(), fields=self.get_child_fields())
        return self.child_form_class(**self.get_form_kwargs())

    def get_context_data(self, **kwargs):
        if 'child_form' not in kwargs:
            kwargs['child_form'] = self.get_child_form()
        return super().get_context_data(**kwargs)

    def post(self, request, *args, **kwargs):
        form = self.get_form()
        child_form = self.get_child_form()

        # check if both forms are valid
        form_valid = form.is_valid()
        child_form_valid = child_form.is_valid()

        if form_valid and child_form_valid:
            return self.form_valid(form, child_form)
        else:
            return self.form_invalid(form)

    def form_valid(self, form, child_form):
        self.object = form.save()
        save_child_form = child_form.save(commit=False)
        save_child_form.course_key = self.object
        save_child_form.save()

        return HttpResponseRedirect(self.get_success_url())

Example Usage:

class ConsumerRegistrationUpdateView(UpdateView):
    model = Registration
    fields = ('firstname', 'lastname',)
    child_model = ConsumerProfile
    child_fields = ('payment_token', 'cart',)

Or with ModelFormClass:

class ConsumerRegistrationUpdateView(UpdateView):
    model = Registration
    fields = ('firstname', 'lastname',)
    child_model = ConsumerProfile
    child_form_class = ConsumerProfileForm

Done. Hope that helps someone.

You probably should take a look at Inline formsets. Inline formsets are used when your models are related by a foreign key.

You can check my answer here for a similar problem.

It talks about how to combine registration and user profile into one form, but it can be generalized to any ModelForm combination.