CODEWITHSUNDEEP
djangoformsfield
olamundo
olamundo

Reputation: 24981

Django: where are the fields stored inside a form instance

Suppose I created a django form that has a radio box selection in it:

class PlaylistsForm(forms.Form):
    choices=forms.ChoiceField( widget=forms.RadioSelect(), CHOICES,label="choices")

If I try to instantiate the form and do form.choices I get an error that the instance has no attribute choices. Can you refer me to somewhere where it explains the magic behind the creation of the fields, and secondly, how can I access the fields?

EDIT: To make it clear: I want to know why, given an instance of PlaylistsForm, doing print form.choices I get an error saying there's no such attribute. What dark magic is happening behind the scenes here?

Upvotes: 0

Views: 637

Answers (1)

Dominic Rodger
Dominic Rodger

Reputation: 99751

Presuming CHOICES is a tuple of options for the field, the change is relatively simple:

class PlaylistsForm(forms.Form):
    choices=forms.ChoiceField(widget=forms.RadioSelect(),
                              choices=CHOICES,
                              label="choices")

See the documentation of ChoiceField, and the documentation of choices for more detail.

Changes post your edit:

Short answer

You're probably confusing your field called choices, and the attribute choices on your choices field.

Say you've got a form:

my_form = PlaylistsForm()

You could access the choices attribute of the choices field like this:

my_form.fields['choices'].choices

Long answer

I didn't know how to do what you wanted, so I stuck a import pdb; pdb.set_trace() just after I declared a form, like this:

form = PlaylistsForm()
import pdb; pdb.set_trace()

Then, using the development server, I opened up a URL which mapped to the view with my new import pdb; pdb.set_trace() in it. Switching over to my command prompt, I could inspect what attributes and methods existed on my form object at the debug prompt:

(Pdb) dir(form)

This showed me form had a fields attribute, so I looked at it:

(Pdb) form.fields

This showed me form.fields is a dict, with values being Field objects, I picked out the choices field, and looked to see what attributes it had:

 (Pdb) dir(form.fields['choices'])

This showed me that form.fields['choices'] had a choices attribute:

(Pdb) form.fields['chiices'].choices
[('', '---------'), (1L, My Playlist')]

This is probably what you're looking for.

Upvotes: 5

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