Use Formsets¶

Problem¶

You want a single page that submits several form rows at once.

Solution¶

Build the formset with Django’s formset_factory, register an action that takes the formset as its form parameter, and render every row in the template.

Walkthrough¶

Define the row form and the formset.

notes/forms.py¶

from django.forms import formset_factory
from next.forms import ModelForm
from notes.models import Note

class NoteRowForm(ModelForm):
    class Meta:
        model = Note
        fields = ("title", "body")

NoteFormSet = formset_factory(NoteRowForm, extra=3, can_delete=True)

notes/pages/notes/bulk/page.py¶

from django.forms.formsets import BaseFormSet
from django.http import HttpResponseRedirect
from django.urls import reverse
from next.forms import action
from notes.forms import NoteFormSet

def build_bulk_formset() -> tuple[type[BaseFormSet], dict]:
    return NoteFormSet, {}

@action("bulk_create", form_class=build_bulk_formset)
def bulk_create(form: NoteFormSet) -> HttpResponseRedirect:
    for row in form:
        if row.cleaned_data and not row.cleaned_data.get("DELETE"):
            row.save()
    return HttpResponseRedirect(reverse("next:page_"))

Passing a formset class directly to form_class raises TypeError at dispatch time because the dispatcher expects a get_initial method on the form class. Register a factory callable that returns a (FormSetClass, init_kwargs) tuple instead. The init_kwargs reach the formset constructor and the dispatcher skips the get_initial step.

The page_{path} URL name follows the file-router naming convention, see File Router.

Render the formset.

notes/pages/notes/bulk/template.djx¶

{% form @action="bulk_create" %}
  {{ form.management_form }}
  {% for row in form %}
    <fieldset>
      <legend>Row {{ forloop.counter }}</legend>
      {{ row.title }}
      {{ row.body }}
    </fieldset>
  {% endfor %}
  <button type="submit">Save all</button>
{% endform %}

Always render {{ form.management_form }} before the row loop.

Clean Up Empty Rows¶

A formset with extra=3 ships three blank rows. When initial data is provided alongside those extra rows, Django pre-populates the blank rows with the initial values. A user who leaves those rows untouched submits data that appears empty but carries hidden values, triggering validation errors. Use cleanup_extra_initial to clear initial values from blank extra rows before the formset is rendered.

notes/pages/notes/bulk/page.py¶

from types import SimpleNamespace

from next.forms import cleanup_extra_initial
from next.pages import context
from notes.forms import NoteFormSet

def build_formset(initial: list[dict]) -> NoteFormSet:
    formset = NoteFormSet(initial=initial)
    cleanup_extra_initial(formset)
    return formset

@context("bulk_create")
def bulk_create_form() -> SimpleNamespace:
    return SimpleNamespace(form=build_formset([{"title": "Draft"}]))

The @context callable named after the action publishes the formset under the key the {% form %} tag reads on the initial render.

Verification¶

Submit the formset with two filled rows and one blank row. The handler saves the two filled rows and skips the blank one. A row that fails validation re-renders with errors on that row only.

Use Formsets¶

Problem¶

Solution¶

Walkthrough¶

Clean Up Empty Rows¶

Verification¶

See Also¶