Django Admin: Chained Filters Not Updating Based on Foreign Key Selections

Using Django The Admin
1

Hey there,

I’ve set up chained filters in Django Admin using foreign keys, but they don’t seem to update dynamically when a parent filter is selected. Has anyone experienced this issue before? What’s the proper way to implement chained filters in Django Admin to ensure they update correctly?

Thanks!

2

Welcome @Leerost !

Please post your Models involved with this, and the corresponding ModelAdmin classes.

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3

One way to achieve this is to define the following filter:

class DependentListFilter(admin.RelatedFieldListFilter):
    def __init__(self, field, request, params, model, model_admin, field_path):
        super().__init__(field, request, params, model, model_admin, field_path)

        query_params = {
            self.dependent_field: id
            for param, id in request.GET.items()
            if param.startswith(self.dependent_field)
        }

        if query_params:
            dep_field = self.dependent_field
            filter = {dep_field + '__in': query_params[dep_field]}
            self.lookup_choices = (
                field.related_model.objects
                .filter(**filter)
                .values_list('id', 'name')
            )

Assuming your model has the foreign keys continent and country, define the filter

class CountryListFilter(DependentListFilter):
    dependent_field = 'continent'

Then in the model admin use the filter as follows:

@admin.register(MyModel)
class MyModelAdmin(admin.ModelAdmin):
    list_display = ['continent', 'country']
    list_filter = [
        ('continent', admin.RelatedFieldListFilter),
        ('country', CountryListFilter)
    ]