Django Autocomplete Light: multiple selection from List (not Model)

Question

I know how to use DAL (Django Autocomplete Light) to allow a single selection from a list, like in the tutorial:

CHOICE_LIST = [
        ['FR', 'France'],
        ['FJ', 'Fiji'],
        ['FI', 'Finland'],
        ['CH', 'Switzerland']
    ]

class CountryAutocompleteFromList(autocomplete.Select2ListView):
    def get_list(self):
        return CHOICE_LIST

class CountryForm(forms.ModelForm):
    country = autocomplete.Select2ListChoiceField(
        choice_list=CHOICE_LIST,
        widget=autocomplete.ListSelect2(url='country-list-autocomplete')
    )

However, I can't find any lead in the documentation or DAL source code to implement multiple selection, e.g. to allow users to pick 2 countries or more, in combination with django.contrib.postgres.fields import ArrayField which I already use in my code.

Has anyone a working example I could learn from?

Answer 1

After a long period of trial and error, the following works.

Say you want to ask a list of emails, optionally with some autocompletion, but also being able to create/add new ones on the fly

class Select2ListCreateMultipleChoiceField(Select2ListCreateChoiceField, Select2Multiple):
    def to_python(self, value):
        if not value:
            return []
        elif not isinstance(value, list):
            return [value]
        return value

    def validate(self, value):
        # for create :
        super(ChoiceField, self).validate(value)
        # otherwise you could use :
        # for v in value:
        #     super().validate(v)

    def bound_data(self, data, initial):
        if self.disabled:
            return initial
        return data


class ListSelect2Multiple(WidgetMixin, Select2WidgetMixin, forms.SelectMultiple):
    """Select widget for regular choices and Select2."""


class EmailsForm(forms.Form):
    emails = Select2ListCreateMultipleChoiceField(
        label="Emails",
        help_text="Emails list",
        widget=ListSelect2Multiple(
            url='........ your view name for autocompletion .......',
        ),
    )

You can then use EmailsForm(request.POST).cleaned_data normally afterward and save it however you'd like.