How to set initial data for Django admin model add instance form?

Question

How can I set an initial value of a field in the automatically generated form for adding a Django model instance, before the form is displayed? I am using Django 1.3.1.

My model is the following:

class Foo(models.Model):
  title = models.CharField(max_length=50)
  description = models.TextField()

and the current admin form is really nothing special

class FooAdmin(admin.ModelAdmin):
  ordering = ('title',)

When I use the admin page to add a new instance of Foo, I get a nice form with empty fields for title and description. What I would like is that the description field is set with a template that I obtain by calling a function.

My current best attempt at getting there is this:

def get_default_content():
  return 'this is a template for a Foo description'

class FooAdminForm(django.forms.ModelForm):

  class Meta:
      model = Foo

  def __init__(self, *args, **kwargs):
      kwargs['initial'].update({'description': get_default_content()})
      super(FooAdminForm, self).__init__(self, *args, **kwargs)

class FooAdmin(admin.ModelAdmin):
  ordering = ('title',)
  form = FooAdminForm

but if I try this I get this Django error:

AttributeError at /admin/bar/foo/add/ 
   'FooForm' object has no attribute 'get'
Request Method: GET
Request URL:    http://localhost:8000/admin/bar/foo/add/
Django Version: 1.3.1
Exception Type: AttributeError
Exception Value:    'FooForm' object has no attribute 'get'
Exception Location: /www/django-site/venv/lib/python2.6/site-packages/django/forms/widgets.py in value_from_datadict, line 178

I don't know what is wrong here, and what I should do to make it work. What I also find strange about this error (apart from the fact that I see it at all) is that there is no FooForm in my code at all?

score 43 · Answer 1 · edited Jun 21 '21 at 20:54

43

Alasdair's approach is nice but outdated. Radev's approach looks quite nice and as mentioned in the comment, it strikes me that there is nothing about this in the documentation.

Apart from those, since Django 1.7 there is a function get_changeform_initial_data in ModelAdmin that sets initial form values:

def get_changeform_initial_data(self, request):
    return {'name': 'custom_initial_value'}

edited Jun 21 '21 at 20:54

djvg

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answered Nov 11 '15 at 10:37

Wtower

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1

for some reason in 1.10.2 this method is not called at all, though it is present in the docs – scythargon Oct 25 '16 at 11:46
@scythargon I just tested it in 1.10.2 and for me it worked as documented. – Wtower Mar 16 '17 at 17:36
2

It's easy to lose track of all the available hooks for ModelAdmin. Thanks for this! – Filip Kilibarda Dec 27 '17 at 21:24
Django 1.11.10 and Django didn't call overrided get_changeform_initial_data method. – valex Apr 01 '18 at 17:43
6

Facing the same issue of the method not being called I dove into the source code. The answer is quite simple, it is only called for newly created objects. Changing an existing object will **not** call it. – Fynn Becker Aug 09 '18 at 15:20
1

Is there a similar function for inlines ? – Josir Apr 20 '19 at 20:27
Does this work with AutoCompleteFields? – Eric O. Dec 02 '21 at 16:01

Alasdair · Accepted Answer · 2019-03-14T10:51:41.850

29

You need to include self as the first argument in your __init__ method definition, but should not include it when you call the superclass' method.

def __init__(self, *args, **kwargs):
    # We can't assume that kwargs['initial'] exists! 
    if 'initial' not in kwargs:
        kwargs['initial'] = {}
    kwargs['initial'].update({'description': get_default_content()})
    super(FooAdminForm, self).__init__(*args, **kwargs)

Having said that, a model field can take a callable for its default, so you may not have to define a custom admin form at all.

class Foo(models.Model):
    title = models.CharField(max_length=50)
    description = models.TextField(default=get_default_content)

edited Mar 14 '19 at 10:51

answered Apr 03 '12 at 21:16

Alasdair

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Wow, that worked like a charm! Awesomely cryptic message by the way for such a silly mistake... Thanks a lot for your help! – Martijn de Milliano Apr 04 '12 at 17:53
By the way, I also tried your second suggestion successfully, which is even cleaner, so thanks again! – Martijn de Milliano Apr 04 '12 at 17:55
I found that setting kwargs['initial'] caused an error when saving the form. I had set an if clause: if 'initial' in kwargs.keys(): kwargs['initial'].update(... This worked for displaying the initial values and updating them. – Sven Dec 17 '12 at 14:11
@Sven good point. I've updated my answer to set `initial` to an empty dict if it isn't in `kwargs`. – Alasdair Dec 17 '12 at 15:47

score 15 · Answer 3 · edited Jun 22 '21 at 08:31

15

More then 3 years later, But actually what you should do is override admin.ModelAdmin formfield_for_dbfield .. like this:

class FooAdmin(admin.ModelAdmin):
    def formfield_for_dbfield(self, db_field, **kwargs):
        field =  super(FooAdmin, self).formfield_for_dbfield(db_field, **kwargs)
        if db_field.name == 'description':
            field.initial = 'My initial description'
        elif db_field.name == 'counter':
            field.initial = get_counter() + 1
        return field

Cheers;

edited Jun 22 '21 at 08:31

djvg

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answered Jun 28 '15 at 01:16

Ramez Ashraf

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Very nice. It is strange but there is no such thing in the documentation: https://docs.djangoproject.com/en/1.8/ref/contrib/admin/ – Wtower Nov 11 '15 at 10:34
The Django admin is "way" under-documented , unfortunately. – Ramez Ashraf Nov 21 '15 at 09:50
Alternatively you could remove the `field = super...` line, set `kwargs['initial'] = 'My initial description'` (and similar for the `'counter'` field), followed by `return super...` That saves a line. – djvg Feb 19 '19 at 20:30

score 3 · Answer 4 · answered Jun 22 '21 at 08:48

When adding new objects, it is convenient to use get_changeform_initial_data() as suggested by Wtower.

However, when changing existing objects, that does not work (see source).

In that case, you could extend ModelAdmin.get_form() as follows (using the OP's example):

def get_form(self, request, obj=None, change=False, **kwargs):
    if obj and not obj.description:
        obj.description = get_default_content()
    return super().get_form(request, obj, change, **kwargs)

How to set initial data for Django admin model add instance form?

4 Answers4

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