Model Formset and regular ModelForm in same template? - django

Question

I got two models:
Project:
class Project(Model):
name = CharField(max_length=50)
members = ManyToManyField("accounts.User", through='ProjectUser')
organization = ForeignKey(Organization, related_name="projects", on_delete=CASCADE)
def __str__(self):
return self.name
and Task:
class Task(Model):
task = CharField(max_length=100)
project = ForeignKey(Project, on_delete=CASCADE)
class Meta:
db_table = 'task'
I got a UpdateView class:
class ProjectUpdateView(UpdateView):
form_class = ProjectUpdateForm
template_name = 'projects/project_edit.html'
success_url = reverse_lazy('projects:list')
How can I allow a user to add tasks (through an inline formset) on the same page as where they'd edit a Project instance?
E.g one consolidated form where the user can edit the Project name, and add / remove Task instances, all in one place

Answer 1

Form/Formset:
First, create a form and a formset for your Task model
class TaskForm(ModelForm):
class Meta:
model = Task
fields = ['task']
def __init__(self, *args, **kwargs):
super(TaskForm, self).__init__(*args, **kwargs)
class TaskBaseFormSet(BaseInlineFormSet):
def __init__(self, *args, **kwargs):
super(TaskBaseFormSet, self).__init__(*args, **kwargs)
TaskFormset = inlineformset_factory(
Project, # parent_model
Task, # model
form=TaskForm,
formset=TaskBaseFormSet
)
Or maybe all that you need to do to create a TaskFormset if you dont need a TaskForm class is this
TaskFormset = inlineformset_factory(Project, Task, fields=('task',))
View:
I see you're using a UpdateView class for your view, so you can do this to get a TaskFormset in your context_data, so now you can use the TaskFormset in the template that you declared in the 'template_name' property of your UpdateView class
def get_context_data(self, **kwargs):
context = super().get_context_data(**kwargs)
if self.request.POST:
context['task_formset'] = forms.TaskFormset(self.request.POST)
else:
context['task_formset'] = forms.TaskFormset()
return context
# In the form_valid method of your UpdateView class you can validate the data
# and assign the Project instance to all the tasks that were create by the formsets
def form_valid(self, form):
task_formset = context['task_formset']
# you can validate formset data like this
if not task_formset.is_valid():
return self.form_invalid(form)
project = form.save()
# Here you assign the Project instance to the Tasks
task_formset.instance = project
task_formset.save()
return super().form_valid(form)
Template:
Now all that you need to do is to print the management_form and each form from the formset using a loop as you can see in the code below
<form method="post">
<!-- Your ProjectUpdateForm form here... -->
{{ task_formset.management_form }}
<table>
{% for form in task_formset %}
{{ form }}
{% endfor %}
</table>
</form>
Hope this can help! There are some links to the official Django documentation that you may find useful:
https://docs.djangoproject.com/en/3.1/topics/forms/formsets/#using-a-formset-in-views-and-templates
https://docs.djangoproject.com/en/3.1/topics/forms/modelforms/#inline-formsets
https://docs.djangoproject.com/en/3.1/ref/forms/models/#inlineformset-factory