Show select as a tree

Question

How to show categories as a tree in Django admin using MPTT?

I made it show list of categories as a tree:

But it does not work when I try to create a new article:

How do I make it render select as a tree?

Here is my model:

# -*- coding: utf-8 -*-
from __future__ import unicode_literals
from django.db import models
from mptt.models import MPTTModel, TreeForeignKey
from ckeditor.fields import RichTextField
from taggit.managers import TaggableManager
import os


class Category(MPTTModel):

    name = models.CharField(u'Заголовок', max_length=100, unique=False)
    parent = TreeForeignKey('self', null=True, blank=True, related_name='children', db_index=True,
                            verbose_name=u'Родитель')

    class Meta:
        verbose_name = u'Мероприятие'
        verbose_name_plural = u'Мероприятия'

    class MPTTMeta:
        order_insertion_by = ['name']

    def __unicode__(self):
        return self.name


class Article(models.Model):
    category = models.ForeignKey(Category, on_delete=models.CASCADE, blank=False, verbose_name=u'Раздел')
    title = models.CharField(u'Содержание', max_length=120, blank=False)
    content = RichTextField(u'Содержание', blank=False)
    tags = TaggableManager(u'Тэги')

    class Meta:
        verbose_name = u'Новость'
        verbose_name_plural = u'Новости'

Answer 1

You should use TreeForeignKey in your child model:

class Article(models.Model):
    category = TreeForeignKey(Category, on_delete=models.CASCADE, blank=False,
    null=False, verbose_name=u'Раздел')
    ...