DjangoのModelFormを利用したフォーム作成でForeignKeyで参照したフィールドを指定する方法

前提・実現したいこと

Djangoチュートリアルの投票アプリケーション（polls）を改良する形でアプリケーションを作っています。ModelFormを利用してフォームを作っているのですが、**Foreign Keyで連携したデータベースのフィールドをどのように表示させればよいのかわかりません。**現状のコード、だとForegin Keyで連携したデータベースのフィールドを含むすべてのフィールドが表示できていますが、ユーザーに変更されたくない値まで表示させてしまっています。

もしくは、

python
1fields = '__all__'

ですべてのフィールドを取り出した場合は、HTMLファイルでどのように表示させるのが良いのでしょうか。

取り出したいフィールド（カラム？）は

question_text
pub_date
question_deadline
choice_text
choice_image

該当のソースコード

python
1forms.py
2
3from django import forms
4from .models import Question, Choice
5
6
7class QuestionCreateForm(forms.ModelForm):
8
9    def __init__(self, *args, **kwargs):
10        super().__init__(*args, **kwargs)
11
12    class Meta:
13        model = Question
14        fields = '__all__'
15
16
17ChoiceFormset = forms.inlineformset_factory(
18    Question, Choice, fields='__all__',
19    extra=2, max_num=5, can_delete=False
20)
21

python
1models.py
2
3mport datetime, os
4
5from django.db import models
6from django.utils import timezone
7
8from mysite.settings import BASE_DIR
9
10# Create your models here.
11
12
13class Question(models.Model):
14    question_text = models.CharField(max_length=200)
15    pub_date = models.DateTimeField('date published')
16    question_deadline = models.DateTimeField(default=timezone.now() + timezone.timedelta(days=1))
17    total_votes = models.IntegerField(default=0)
18
19    def __str__(self):
20        return self.question_text
21
22    def was_published_recently(self):
23        now = timezone.now()
24        return now - datetime.timedelta(days=1) <= self.pub_date <= now
25    was_published_recently.admin_order_field = 'pub_date'
26    was_published_recently.boolean = True
27    was_published_recently.short_description = 'Published recently?'
28
29
30class Choice(models.Model):
31    question = models.ForeignKey(Question, on_delete=models.CASCADE)
32    choice_text = models.CharField(max_length=200)
33    choice_image = models.ImageField(upload_to='polls', default=os.path.join(BASE_DIR, '/polls/default_icon.jpg'))
34    votes = models.IntegerField(default=0)
35
36    def __str__(self):
37        return self.choice_text
38

html
1new.html
2
3{% extends 'polls/base.html' %}
4
5{% block content %}
6<form action="{% url 'polls:add_question' %}" method="post">
7    <h2>記事</h2>
8    {{ form.as_p }}
9
10    <h2>添付ファイル</h2>
11    {{ formset.management_form }}
12    {% for file_form in formset %}
13        {{ file_form.as_p }}
14        <hr>
15    {% endfor %}
16
17    {% csrf_token %}
18    <button type="submit" class="btn btn-primary">送信</button>
19</form>
20
21{% endblock %}

python
1views.py
2
3...
4
5def add_question(request):
6    form = QuestionCreateForm(request.POST or None)
7    context = {'form': form}
8    if request.method == 'POST' and form.is_valid():
9        question = form.save(commit=False)
10        formset = ChoiceFormset(request.POST, files=request.FILES, instance=question)
11        if formset.is_valid():
12            question.save()
13            formset.save()
14            return redirect('polls:index')
15
16        else:
17            context['formset'] = formset
18
19    else:
20        context['formset'] = ChoiceFormset()
21
22    return render(request, 'polls/new.html', context)

実際に表示されるフォーム

試したこと

fieldsを表示させたいフィールドだけにしてみましたがForegin Keyで連携させているフィールドを指定するとエラーが出ます。

python
1forms.py
2
3from django import forms
4from .models import Question, Choice
5
6
7class QuestionCreateForm(forms.ModelForm):
8
9    def __init__(self, *args, **kwargs):
10        super().__init__(*args, **kwargs)
11
12    class Meta:
13        model = Question
14        fields = ('question_text', 'pub_date', 'question_deadline', 'choice_text', 'choice_image')
15
16
17ChoiceFormset = forms.inlineformset_factory(
18    Question, Choice, fields='__all__',
19    extra=2, max_num=5, can_delete=False
20)
21

エラーメッセージ

(venv) ttmone:mysite gaku$ python manage.py runserver
Watching for file changes with StatReloader
Performing system checks...

System check identified no issues (0 silenced).
August 21, 2019 - 06:03:07
Django version 2.2.4, using settings 'mysite.settings'
Starting development server at http://127.0.0.1:8000/
Quit the server with CONTROL-C.
Not Found: /
[21/Aug/2019 06:03:25] "GET / HTTP/1.1" 404 2153
[21/Aug/2019 06:03:33] "GET /polls/ HTTP/1.1" 200 976
[21/Aug/2019 06:03:33] "GET /static/polls/style.css HTTP/1.1" 304 0
[21/Aug/2019 06:03:36] "GET /polls/add/ HTTP/1.1" 200 3292
^C(venv) ttmone:mysite gaku$ python manage.py runserver
Watching for file changes with StatReloader
Performing system checks...

Exception in thread django-main-thread:
Traceback (most recent call last):
  File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/threading.py", line 917, in _bootstrap_inner
    self.run()
  File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/threading.py", line 865, in run
    self._target(*self._args, **self._kwargs)
  File "/Users/gaku/Programing/mysite/venv/lib/python3.7/site-packages/django/utils/autoreload.py", line 54, in wrapper
    fn(*args, **kwargs)
  File "/Users/gaku/Programing/mysite/venv/lib/python3.7/site-packages/django/core/management/commands/runserver.py", line 117, in inner_run
    self.check(display_num_errors=True)
  File "/Users/gaku/Programing/mysite/venv/lib/python3.7/site-packages/django/core/management/base.py", line 390, in check
    include_deployment_checks=include_deployment_checks,
  File "/Users/gaku/Programing/mysite/venv/lib/python3.7/site-packages/django/core/management/base.py", line 377, in _run_checks
    return checks.run_checks(**kwargs)
  File "/Users/gaku/Programing/mysite/venv/lib/python3.7/site-packages/django/core/checks/registry.py", line 72, in run_checks
    new_errors = check(app_configs=app_configs)
  File "/Users/gaku/Programing/mysite/venv/lib/python3.7/site-packages/django/core/checks/urls.py", line 40, in check_url_namespaces_unique
    all_namespaces = _load_all_namespaces(resolver)
  File "/Users/gaku/Programing/mysite/venv/lib/python3.7/site-packages/django/core/checks/urls.py", line 57, in _load_all_namespaces
    url_patterns = getattr(resolver, 'url_patterns', [])
  File "/Users/gaku/Programing/mysite/venv/lib/python3.7/site-packages/django/utils/functional.py", line 80, in __get__
    res = instance.__dict__[self.name] = self.func(instance)
  File "/Users/gaku/Programing/mysite/venv/lib/python3.7/site-packages/django/urls/resolvers.py", line 579, in url_patterns
    patterns = getattr(self.urlconf_module, "urlpatterns", self.urlconf_module)
  File "/Users/gaku/Programing/mysite/venv/lib/python3.7/site-packages/django/utils/functional.py", line 80, in __get__
    res = instance.__dict__[self.name] = self.func(instance)
  File "/Users/gaku/Programing/mysite/venv/lib/python3.7/site-packages/django/urls/resolvers.py", line 572, in urlconf_module
    return import_module(self.urlconf_name)
  File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1006, in _gcd_import
  File "<frozen importlib._bootstrap>", line 983, in _find_and_load
  File "<frozen importlib._bootstrap>", line 967, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 677, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 728, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "/Users/gaku/Programing/mysite/mysite/urls.py", line 22, in <module>
    path('polls/', include('polls.urls')),
  File "/Users/gaku/Programing/mysite/venv/lib/python3.7/site-packages/django/urls/conf.py", line 34, in include
    urlconf_module = import_module(urlconf_module)
  File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1006, in _gcd_import
  File "<frozen importlib._bootstrap>", line 983, in _find_and_load
  File "<frozen importlib._bootstrap>", line 967, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 677, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 728, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "/Users/gaku/Programing/mysite/polls/urls.py", line 3, in <module>
    from . import views
  File "/Users/gaku/Programing/mysite/polls/views.py", line 7, in <module>
    from .forms import QuestionCreateForm, ChoiceFormset
  File "/Users/gaku/Programing/mysite/polls/forms.py", line 12, in <module>
    class QuestionCreateForm(forms.ModelForm):
  File "/Users/gaku/Programing/mysite/venv/lib/python3.7/site-packages/django/forms/models.py", line 266, in __new__
    raise FieldError(message)
django.core.exceptions.FieldError: Unknown field(s) (choice_text, choice_image) specified for Question

ForeignKeyで参照しているフィールドの指定がうまくいっていないのだと思います。

なお、下のコードだと通ります。

python
1forms.py
2
3from django import forms
4from .models import Question, Choice
5
6
7class QuestionCreateForm(forms.ModelForm):
8
9    def __init__(self, *args, **kwargs):
10        super().__init__(*args, **kwargs)
11
12    class Meta:
13        model = Question
14        fields = ('question_text', 'pub_date', 'question_deadline')
15
16
17ChoiceFormset = forms.inlineformset_factory(
18    Question, Choice, fields='__all__',
19    extra=2, max_num=5, can_delete=False
20)
21