adding new form fields dynamically in admin

Question

I am trying to add dynamically new form fields (I used this blog post), for a form used in admin interface :

class ServiceRoleAssignmentForm(forms.ModelForm):

    class Meta:
        model = ServiceRoleAssignment

    def __init__(self, *args, **kwargs):
        super(ServiceRoleAssignmentForm, self).__init__(*args, **kwargs)
        self.fields['test'] = forms.CharField(label='test') 


class ServiceRoleAssignmentAdmin(admin.ModelAdmin):
    form = ServiceRoleAssignmentForm

admin.site.register(ServiceRoleAssignment, ServiceRoleAssignmentAdmin)

However, no matter what I try, the field doesn't appear on my admin form ! Could it be a problem related to the way admin works ? Or to ModelForm ?

Thank for any help !

Sébastien

PS : I am using django 1.3

Oleg · Accepted Answer · 2011-04-20 09:14:06Z

3

When rendering your form in template, fields enumerating from fieldsets variable, not from fields. Sure you can redefine fieldsets in your AdminForm, but then validations will fail as original form class doesn't have such field. One workaround I can propose is to define this field in form definition statically and then redefine that field in form's init method dynamically. Here is an example:

class ServiceRoleAssignmentForm(forms.ModelForm):
    test = forms.Field()

    class Meta:
        model = ServiceRoleAssignment

    def __init__(self, *args, **kwargs):
        super(ServiceRoleAssignmentForm, self).__init__(*args, **kwargs)
        # Here we will redefine our test field.
        self.fields['test'] = forms.CharField(label='test2')

answered Apr 20, 2011 at 9:14

Oleg

462 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

sebpiq Over a year ago

Thanks for the answer ! I was thinking about doing that actually ... But I didn't get this part "fields enumerating from fieldsets variable, not from fields. Sure you can redefine fieldsets in your AdminForm". What's that fieldsets variable ? You mean that there is a "fields" variable that contains all fields, and a "fieldsets" that is used for rendering them ? In that case why not adding the new field to both "fieldsets" AND "fields" ???

Brenda J. Butler Over a year ago

Have a look at the template. You might want to override the template (or update it if you're already overriding it).

Andre · Accepted Answer · 2011-04-19 20:35:03Z

I actually have a the same issue which I'm working through at the moment. While not ideal, I have found a temporary workaround that works for my use case. It might be of use to you?

In my case I have a static name for the field, so I just declared it in my ModelForm. as normal, I then override the init() as normal to override some options.

ie:

def statemachine_form(for_model=None):
    """
    Factory function to create a special case form
    """
    class _StateMachineBaseModelForm(forms.ModelForm):
        _sm_action = forms.ChoiceField(choices=[], label="Take Action")

        class Meta:
            model = for_model

        def __init__(self, *args, **kwargs):
            super(_StateMachineBaseModelForm, self).__init__(*args, **kwargs)
            actions = (('', '-----------'),)
            for action in self.instance.sm_state_actions():
                actions += ((action, action),)
            self.fields['_sm_action'] = forms.ChoiceField(choices=actions,
                                                          label="Take Action")
    if for_model: return _StateMachineBaseModelForm

class ContentItemAdmin(admin.ModelAdmin):
    form = statemachine_form(for_model=ContentItem)

Now as I mentioned before, this is not entirely 'dynamic', but this will do for me for the time being.

I have the exact same problem that, if I add the field dynamically, without declaring it first, then it doesn't actually exist. I think this does in fact have something to do with the way that ModelForm creates the fields.

I'm hoping someone else can give us some more info.

oh you may notice I'm using a factory function to generate the form. This is part of me trying to find the solution. I ran across docs on this here: b-list.org/weblog/2008/nov/09/dynamic-forms
Well ... that could work indeed ! I could for example declare 10 useless fields with hidden input, and then "toggle them on" dynamically ... But that's not very beautiful. Thanks for this workaround ! For the moment, I will just go-on with declaring the fields statically ...

Community · Accepted Answer · 2017-05-23 11:58:19Z

0

Django - Overriding get_form to customize admin forms based on request

edited May 23, 2017 at 11:58

CommunityBot

11 silver badge

answered May 29, 2011 at 18:32

Googol

2,9432 gold badges23 silver badges13 bronze badges

Comments

Marcos Dumay · Accepted Answer · 2012-11-19 22:53:15Z

-2

Try to add the field before calling the super.init:

def __init__(self, *args, **kwargs):
    self.fields['test'] = forms.CharField(label='test') 
    super(ServiceRoleAssignmentForm, self).__init__(*args, **kwargs)

answered Nov 19, 2012 at 22:53

Marcos Dumay

1651 silver badge3 bronze badges

1 Comment

David Reynolds Over a year ago

The fields attribute doesn't exist until after you call super on the form.

Collectives™ on Stack Overflow

adding new form fields dynamically in admin

4 Answers 4

2 Comments

2 Comments

Comments

1 Comment

Linked

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

2 Comments

2 Comments

Comments

1 Comment

Linked

Related