[Django]-Passing initial into Django's ModelFormSet

You are passing an empty queryset to ModelFormset.

ExampleModelFormSet = modelformset_factory(ExampleModel, extra=2)
formset = ExampleModelFormSet(queryset=ExampleModel.objects.none(),
                          initial=[{'name': 'Some Name'},
                                   {'name': 'Another Name'}])

which is indeed the way to achieve what you want. It makes sense to pass an empty queryset, else initial values will override the model’s database value.

And if I suppose, you are passing a non-empty queryset, and yet want your extra forms to be filled will initial values, you can override the Formset.

from django.forms.models import modelformset_factory  
ExampleFormset = modelformset_factory(OpenIDProfile, extra=3)

class myFormset(ExampleFormset):

    def _construct_form(self, i, **kwargs):
        """
        Instantiates and returns the i-th form instance in a formset.
        """
        if self.is_bound and i < self.initial_form_count():
            pk_key = "%s-%s" % (self.add_prefix(i), self.model._meta.pk.name)
            pk = self.data[pk_key]
            pk_field = self.model._meta.pk
            pk = pk_field.get_db_prep_lookup('exact', pk)
            if isinstance(pk, list):
                pk = pk[0]
            kwargs['instance'] = self._existing_object(pk)
        if i < self.initial_form_count() and not kwargs.get('instance'):
            kwargs['instance'] = self.get_queryset()[i]

        defaults = {'auto_id': self.auto_id, 'prefix': self.add_prefix(i)}
        if self.data or self.files:
            defaults['data'] = self.data
            defaults['files'] = self.files
        # Check to confirm we are not overwriting the database value.
        if not i in range(self.initial_form_count()) and self.initial:
            try:
                defaults['initial'] = self.initial[i - self.initial_form_count()]
            except IndexError:
                pass
        # Allow extra forms to be empty.
        if i >= self.initial_form_count():
            defaults['empty_permitted'] = True
        defaults.update(kwargs)
        form = self.form(**defaults)
        self.add_fields(form, i)        
        return form

Note: initial is list of dicts. Its desirable to have items in list exactly equal to the number of extra.

New in Django 1.4 …if you set initial on a modelformset it now only applies to the ‘extra’ forms, not those bound to instances from the queryset:

https://docs.djangoproject.com/en/dev/topics/forms/modelforms/#providing-initial-values

So the various hacks above are no longer necessary and using initial is the answer.

The best way I’ve found to do this is to just manually adjust the formset object’s “extra” attribute after initialization. This has been tested and works in Django 1.9.

ExampleModelFormSet = modelformset_factory(ExampleModel, extra=1)
formset = ExampleModelFormSet(initial=[{'name': 'Some Name'},
                                       {'name': 'Another Name'}])
formset.extra = 3

This will spit out 3 forms (2 prepopulated and 1 blank).

If you want something more dynamic (e.g. initial is a var calculated somewhere else), you can do something like this:

ExampleModelFormSet = modelformset_factory(ExampleModel, extra=1)
formset = ExampleModelFormSet(initial=initial)
formset.extra += len(initial)

Hope that helps.

It is still possible to pass initial to a ModelFormSet.

from django.forms.models import modelformset_factory
from example.models import ExampleModel

ExampleModelFormSet = modelformset_factory(ExampleModel)
formset = ExampleModelFormSet(initial=[{'name': 'Some Name'},
                                       {'name': 'Another Name'}])

If this is not what your after, can you explain your question more.

EDIT:

ExampleModelFormSet = modelformset_factory(ExampleModel, extra=2)
formset = ExampleModelFormSet(queryset=ExampleModel.objects.none(),
                              initial=[{'name': 'Some Name'},
                                       {'name': 'Another Name'}])

In Django 1.4 the rule changed: the number of initials to be displayed corresponds to “extra” parameter.
https://docs.djangoproject.com/en/dev/topics/forms/modelforms/#providing-initial-values

In my case the count of initial parameters varies dynamically, so
I found the following way:

initial=[{'name': 'Some Name'},{'name': 'Another Name'}]
formset = ExampleModelFormSet(queryset=ExampleModel.objects.none(),
                      initial=initial, extra=len(initial))


class MyBaseFormSet(BaseModelFormSet):
    def __init__(self, *args, **kwargs):
        self.extra = kwargs.pop('extra', self.extra)
        super(MyBaseFormSet, self).__init__(*args, **kwargs)

provided, ExampleModelFormSet is based on MyBaseFormSet

A simple solution could be that you pass a form that extends a modelform() to a formset (rather than modelformset).

That way you can set initial values in the form.

I think you can use initial argument, as with regular formsets
http://docs.djangoproject.com/en/dev/topics/forms/formsets/#using-initial-data-with-a-formset

You can alter the initial data afterwards.

For example:

# Construct the FormSet class
ExampleFormSet = modelformset_factory(ParentModel, ChildModel)

# Set the initial data
initial_data = {'field1': 1}
for form in ExampleFormSet.extra_forms:
    for field in form.fields:
        field.initial = initial_data[field.name]

The simple way how to pass initial data with the same count of extra forms:

MyModelFormSet = lambda *a, **kw: modelformset_factory(MyModel, extra=kw.pop('extra', 1))(*a, **kw)

Usage in views:

initial=[{'name': 'Some Name'},{'name': 'Another Name'}
formset = MyModelFormSet(queryset=MyModel.objects.none(), initial, extra=len(initial))})

Affter two days found this: http://streamhacker.com/2010/03/01/django-model-formsets/

def custom_field_callback(field):
    return field.formfield(required=False)

FormSet = modelformset_factory(model, formfield_callback=custom_field_callback)

def custom_field_callback(field):
    if field.name == 'optional':
        return field.formfield(required=False)
    elif field.name == 'text':
        return field.formfield(widget=Textarea)
    elif field.name == 'integer':
        return IntegerField()
    else:
        return field.formfield()