CODEWITHSUNDEEP
djangoformsmodeladmin
Martijn de Milliano
Martijn de Milliano

Reputation: 3958

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

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?

Upvotes: 33

Views: 46370

Answers (4)

djvg
djvg

Reputation: 14325

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)

Upvotes: 4

Ramez Ashraf
Ramez Ashraf

Reputation: 891

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;

Upvotes: 15

Wtower
Wtower

Reputation: 19922

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'}

Upvotes: 44

Alasdair
Alasdair

Reputation: 309089

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)

Upvotes: 32

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