Use custom select option labels for ModelMultipleChoiceFilter instead of __str__(self)?

[tombreit]

I am using the ModelMultipleChoiceFilter, but like to customize the text of the options (here: instances of models.Author) displayed to the user? Currently these options/labels are the models __str__(self) method.

As I already provide a custom queryset, I would like to provide a custom "label template" or overwrite the default select option labels:

def authors_site_scoped(request):
    return Author.objects.filter(...).distinct()

class PublicationFilter(django_filters.FilterSet):

    authors_filter = django_filters.ModelMultipleChoiceFilter(
        field_name="authors",
        queryset=authors_site_scoped, 
    )

    class Meta:
        model = Publication
        form = PublicationFilterForm
        fields = (
            "authors_filter",
        )

Is that possible? And if: how :-)?

[carltongibson]

https://docs.djangoproject.com/en/5.0/ref/forms/fields/#django.forms.ModelChoiceField.iterator

[tombreit]

Thank you very much - works perfectly! And for my future self:

class AuthorModelMultipleChoiceField(forms.ModelMultipleChoiceField):
    def label_from_instance(self, obj):
        return obj.get_select_label  # or return f"{obj.last_name}, {obj.first_name}"

class AuthorModelMultipleChoiceFilter(django_filters.ModelMultipleChoiceFilter):
    field_class = AuthorModelMultipleChoiceField

class PublicationFilter(django_filters.FilterSet):
    authors_filter = AuthorModelMultipleChoiceFilter(
        field_name="authors",
    )

Unfortunately, it was not possible to set the field_class=AuthorModelMultipleChoiceField directly for authors_filter (Field.__init__() got an unexpected keyword argument 'field_class').