Question

in the list filter of a model in my Django admin I have a filter Category, and I would like to add a filter Sub-category, which values depend on the selected Category value.

How can I achieve this using ModelAdmin.list_filter?

Thank you

Answer 1

Create a class inherting from SimpleListFilter for the Sub-Category.

Inside the method lookups check if inside the request.GET there is the matching querystring for Category, if there is, make a queryset based on this filter.

Should look something like that: (change according to your real models..might have syntax error, I didn’t test the code, but it should look very similar)

class SubCategoryFilter(SimpleListFilter):
    title = 'sub category'
    parameter_name = 'sub_category'

    def lookups(self, request, model_admin):
        sub_categories = Category.objects;
        if 'category' in request.GET:
             sub_categories = sub_categories.filter(main_category=request.GET['category'])
        return (
            (sub_cat.pk,sub_cat.text) for sub_cat in sub_categories
        )