How can I use "add_fields" in django? - django

Question

I was reading django docs and found the add_fields method.
The documentation says:
"If you need to add additional fields to the formset this can be
easily accomplished. The formset base class provides an add_fields
method."
I want to use it but there is no example or explanation how
it can be used in views and templates. Can you provide me a small
example of using this method?

Answer 1

I will give a small example.
The models.py looks like this,
from django.db import models
class Article(models.Model):
title = models.CharField(max_length=100)
pub_date = models.DateTimeField(auto_now_add=True)
def __str__(self):
return self.title
forms.py looks like this,
from django import forms
from django.forms import BaseFormSet
from .models import Article
class ArticleForm(forms.ModelForm):
class Meta:
model = Article
fields = ['title']
class BaseArticleFormSet(BaseFormSet):
def add_fields(self, form, index):
super().add_fields(form, index)
form.fields['body'] = forms.CharField()
views.py looks like this,
from django.shortcuts import render
from django.forms import formset_factory
from .forms import ArticleForm, BaseArticleFormSet
def home(request):
ArticleFormSet = formset_factory(ArticleForm, formset=BaseArticleFormSet, extra=3)
context = dict()
formset = ArticleFormSet()
if request.method == 'POST':
formset = ArticleFormSet(request.POST)
if formset.is_valid():
print(formset.cleaned_data)
context['formset'] = formset
return render(request, 'home.html', context)
Finally, home.html will look like this,
<form method="post">
{% csrf_token %}
<table>
{{ formset }}
</table>
<button type="submit">submit</button>
</form>
As you can see, the body field appears in templates but it is not included in the the Article model.
Hope that helps!