Specifying widget for model form extra field (Django)

Question

I have to add extra field to my model form. My approach is:

class MyForm(forms.ModelForm):
    extra_field = forms.CharField()
    class Meta:
        model = MyModel
        widgets = {
            #Does not work
            'extra_field': forms.Textarea(attrs={'placeholder': u'Bla bla'}),
        }

But it seems that widget definition for extra_field at class Meta is ignored, because i have a bare input tag instead of textarea on a template. So I apply next approach:

class MyForm(forms.ModelForm):
    #It works fine
    extra_field = forms.CharField(widget=forms.Textarea())
    class Meta:
        model = MyModel

It works perfectly for me, but I used to specify widgets for form fields at class Meta declaration. So I wonder:

Why my first approach doesn't work? What I am doing wrong?

Curitiba

Are you sure you are on Django 1.4 ? Form.Meta.widgets was introduced in Django 1.4. – Algar

Answer 1

It doesn't matter if it's an extra field. This works:

class FooForm(forms.ModelForm):
    class Meta:
        model = People
        widgets = { 
            'name': forms.Textarea(attrs={'placeholder': u'Bla bla'}),
        }   

This doesn't:

class FooForm(forms.ModelForm):
    name = forms.CharField()

    class Meta:
        model = People
        widgets = { 
            'name': forms.Textarea(attrs={'placeholder': u'Bla bla'}),
        }

This is not documented indeed, that's the best I could find in the docs that could relate to that behaviour (maybe it doesn't, it's just the best i could find):

If you explicitly instantiate a form field like this, Django assumes that you want to completely define its behavior [...] you must set the relevant arguments explicitly when declaring the form field.

The implementation of this behaviour is in django/forms/models.py line 219:

   204         if opts.model:
   205             # If a model is defined, extract form fields from it.
   206             fields = fields_for_model(opts.model, opts.fields,
   207                                       opts.exclude, opts.widgets, formfield_callback)
   208             # make sure opts.fields doesn't specify an invalid field
   209             none_model_fields = [k for k, v in fields.iteritems() if not v]
   210             missing_fields = set(none_model_fields) - \
EE 211                              set(declared_fields.keys())
   212             if missing_fields:
   213                 message = 'Unknown field(s) (%s) specified for %s'
   214                 message = message % (', '.join(missing_fields),
   215                                      opts.model.__name__)
   216                 raise FieldError(message)
   217             # Override default model fields with any custom declared ones
   218             # (plus, include all the other declared fields).
   219             fields.update(declared_fields)

After line 206, fields['name'].widget is indeed the Textarea specified in Meta.widgets.

At line 219, fields is updated with declared_fields, and fields['name'].widget becomes django.forms.widgets.TextInput which is the default for CharField.

Apparently, explicit field definitions have priority.

Thanks for asking, good to know, great question.

Algar

this answer doesn't work for me. maybe django changed the behavior – Miru

This is still supposed to work, perhaps make another question ? – Algar

Can we do this in views.py – Torus

Answer 2

I solved the situation above with the following:

class FooForm(forms.ModelForm):
    name = forms.CharField(widget=TextArea(attrs={'placeholder': u'Bla bla'}))
    class Meta:
        model = People

Predominate

Does this add the field name to the table too? – Legofmutton