How to use can_add_related in Django Admin

Question

I've read about the can_add_related feature here: https://code.djangoproject.com/ticket/9071

I tried using it this way:

def get_form(self, request, obj=None, **kwargs):
    self.fields['person'].can_add_related = False
    return super(OperationAdmin, self).get_form(request, obj, **kwargs)

But this throws a TypeError and I don't know how to solve this.

Can someone point me in the right direction?

Thank you.

Answer 1

Another approach, if you are defining an Inline model and use it in your admin, would be to overwrite the get_formset method:

from django.contrib import admin


class MyModelInline(admin.TabularInline):
    model = MyModel
    extra = 0
    min_num = 1
    max_num = 10
    fields = [
        'some_field'
    ]

    def get_formset(self, request, obj=None, **kwargs):
        fs = super().get_formset(request, obj, **kwargs)
        fs.form.base_fields['some_field'].widget.can_add_related = False
        fs.form.base_fields['some_field'].widget.can_change_related = False
        fs.form.base_fields['some_field'].widget.can_delete_related = False
        return fs

Answer 2

This is probably coming in late. But for other viewers reference,

def get_form(self, request, obj=None, **kwargs):
    form = super(ProductAdmin, self).get_form(request, obj, **kwargs)
    form.base_fields['category'].widget.can_add_related = False
    return form

Answer 3

can_add_related seems to be an attribute on the widget, not the field, so try:

self.fields['person'].widget.can_add_related = False

Answer 4

Alternative approach, with changing widget options *before* the form is instantiated:

class MyAdmin(django.contrib.admin.ModelAdmin):

    def formfield_for_dbfield(self, *args, **kwargs):
        formfield = super().formfield_for_dbfield(*args, **kwargs)
        if hasattr(formfield, "widget"):
            formfield.widget.can_add_related = False
            formfield.widget.can_delete_related = False
            formfield.widget.can_change_related = False
        else:
            pass  # this relation doesn't have an admin page to add/delete/change

        return formfield