Inline formset in Django - removing certain fields

Question

I need to create an inline formset which

a) excludes some fields from MyModel being displayed altogether

b) displays some some fields MyModel but prevents them from being editable.

I tried using the code below, using values() in order to filter the query set to just those values I wanted returned. However, this failed.

Anybody with any idea?

class PointTransactionFormset(BaseInlineFormSet):
    def get_queryset(self):
        qs = super(PointTransactionFormset, self).get_queryset()
        qs = qs.filter(description="promotion feedback")
        qs = qs.values('description','points_type') # this does not work
        return qs

class PointTransactionInline(admin.TabularInline):
    model = PointTransaction
    #formset = points_formset()
    #formset = inlineformset_factory(UserProfile,PointTransaction)
    formset = PointTransactionFormset

Solution 1

One thing that doesn't seem to be said in the documentation is that you can include a form inside your parameters for model formsets. So, for instance, let's say you have a person modelform, you can use it in a model formset by doing this

PersonFormSet = inlineformset_factory(User, Person, form=PersonForm, extra=6)

This allows you to do all the form validation, excludes, etc on a modelform level and have the factory replicate it.

Solution 2

Is this a formset for use in the admin? If so, just set "exclude = ['field1', 'field2']" on your InlineModelAdmin to exclude fields. To show some fields values uneditable, you'll have to create a simple custom widget whose render() method just returns the value, and then override the formfield_for_dbfield() method to assign your widget to the proper fields.

If this is not for the admin, but a formset for use elsewhere, then you should make the above customizations (exclude attribute in the Meta inner class, widget override in __init__ method) in a ModelForm subclass which you pass to the formset constructor. (If you're using Django 1.2 or later, you can just use readonly_fields instead).

I can update with code examples if you clarify which situation you're in (admin or not).

Solution 3

I just had a similar issue (not for admin - for the user-facing site) and discovered you can pass the formset and fields you want displayed into inlineformset_factory like this:

factory = inlineformset_factory(UserProfile, PointTransaction, 
                formset=PointTransactionFormset,
                fields=('description','points_type'))
formset = factory(instance=user_profile, data=request.POST)

where user_profile is a UserProfile.

Be warned that this can cause validation problems if the underlying model has required fields that aren't included in the field list passed into inlineformset_factory, but that's the case for any kind of form.