删除时 Django 管理错误

Question

我有一个奇怪的错误：

TypeError at /admin/wall/articles/
__str__ returned non-string (type Articles)

我有一个模型文章。 我只是尝试从 Django 的管理面板中删除我的数据库中的一些文章。我说这很奇怪，因为它只发生在某些物体上。我可以删除大部分文章，但由于某种原因，如果我删除它们，数据库中的某些条目会返回错误。我的其他模型不会发生这种情况。

这是 phpmyadmin 的屏幕截图，显示了我的“文章”表中的所有条目：

例如，我有一个 id 为 70 的条目。在 Django 管理面板中我无法删除它，我有一个错误。为了测试重新创建确切的条目（参见 id 75），我可以从 django 管理面板中删除此条目。

为什么我可以删除一些内容而不是全部？

这是我的models.py：

from django.db import models
from start.models import Games
from django.contrib.auth.models import User
from tinymce.models import HTMLField

# Create your models here.

def user_directory_path_articles(instance, filename):
    return 'media/user/user_{0}/articles/{1}/'.format(instance.user.id, filename)

def user_directory_path_comments(instance, filename):
    return 'media/user/user_{0}/comments/{1}/'.format(instance.user.id, filename)

def validate_file_extension(value):
    import os
    from django.core.exceptions import ValidationError
    ext = os.path.splitext(value.name)[1]  # [0] returns path+filename
    valid_extensions = ['.jpg', '.png']
    if not ext.lower() in valid_extensions:
        raise ValidationError(u'Merci d\'utiliser le format JPG ou PNG')

class Articles(models.Model):
    title = models.CharField(max_length=50, null=False, verbose_name="Titre")
    text = HTMLField()
    image = models.FileField(upload_to='media/articles/', validators=[validate_file_extension], blank=True, null=True, verbose_name="Image de présentation")
    games = models.ForeignKey(Games, verbose_name="Jeux", blank=True, null=True)
    author = models.ForeignKey(User, verbose_name="Auteur")
    is_statut = models.BooleanField(default=True, verbose_name="Statut")
    date = models.DateTimeField(auto_now_add=True, auto_now=False, verbose_name="Date de création")
    update = models.DateTimeField(auto_now=True, verbose_name="Dernière modification")

    def __str__(self):
        return self.title

class Comments(models.Model):
    text = models.CharField(max_length=300, null=False)
    image = models.FileField(upload_to=user_directory_path_comments, validators=[validate_file_extension], blank=True, null=True)
    articles = models.ForeignKey(Articles, verbose_name="Article", null=False, related_name='comments')
    author = models.ForeignKey(User, verbose_name="Auteur")
    in_answer_to = models.ForeignKey('self', verbose_name="En réponse au commentaire", blank=True, null=True, on_delete=models.CASCADE)
    date = models.DateTimeField(auto_now_add=True, auto_now=False, verbose_name="Date de création")
    update = models.DateTimeField(auto_now=True, verbose_name="Dernière modification")

    def __str__(self):
        return self.text

class Like(models.Model):
    articles = models.ForeignKey(Articles, verbose_name="Article", null=True, blank=True)
    user = models.ForeignKey(User, verbose_name="Auteur", null=False)

    def __str__(self):
        return self.articles

class Up(models.Model):
    comments = models.ForeignKey(Comments, verbose_name="Commentaire", null=True, blank=True)
    user = models.ForeignKey(User, verbose_name="Auteur", null=False)

这是我的 admin.py ：

from django.contrib import admin
from .models import Articles, Comments

# Register your models here.

class ArticlesAdmin(admin.ModelAdmin):
    list_display = ('date', 'title', 'author', 'games', 'is_statut', 'update')


    fieldsets = (
        ('Général', {
            'fields': ('title', 'author', 'is_statut')
            }),
        ('Choisir une image de présentation', {
            'fields': ('image',)}),     
        ('Contenu de l\'article', {
            'fields': ('text',)}),
        ('En rapport avec le jeu :', {
            'fields': ('games',)}),
    )
admin.site.register(Articles, ArticlesAdmin)

这是我的错误页面的回溯，感谢您的帮助：

Environment:


Request Method: POST
Request URL: http://*******:8000/admin/wall/articles/

Django Version: 1.11.2
Python Version: 3.5.3
Installed Applications:
['django.contrib.admin',
 'django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.messages',
 'django.contrib.staticfiles',
 'widget_tweaks',
 'tinymce',
 'start',
 'myaccount',
 'wall']
Installed Middleware:
['django.middleware.security.SecurityMiddleware',
 'django.contrib.sessions.middleware.SessionMiddleware',
 'django.middleware.common.CommonMiddleware',
 'django.middleware.csrf.CsrfViewMiddleware',
 'django.contrib.auth.middleware.AuthenticationMiddleware',
 'django.contrib.messages.middleware.MessageMiddleware',
 'django.middleware.clickjacking.XFrameOptionsMiddleware']



Traceback:

File "/usr/local/lib/python3.5/dist-packages/django/core/handlers/exception.py" in inner
  41.             response = get_response(request)

File "/usr/local/lib/python3.5/dist-packages/django/core/handlers/base.py" in _get_response
  187.                 response = self.process_exception_by_middleware(e, request)

File "/usr/local/lib/python3.5/dist-packages/django/core/handlers/base.py" in _get_response
  185.                 response = wrapped_callback(request, *callback_args, **callback_kwargs)

File "/usr/local/lib/python3.5/dist-packages/django/contrib/admin/options.py" in wrapper
  551.                 return self.admin_site.admin_view(view)(*args, **kwargs)

File "/usr/local/lib/python3.5/dist-packages/django/utils/decorators.py" in _wrapped_view
  149.                     response = view_func(request, *args, **kwargs)

File "/usr/local/lib/python3.5/dist-packages/django/views/decorators/cache.py" in _wrapped_view_func
  57.         response = view_func(request, *args, **kwargs)

File "/usr/local/lib/python3.5/dist-packages/django/contrib/admin/sites.py" in inner
  224.             return view(request, *args, **kwargs)

File "/usr/local/lib/python3.5/dist-packages/django/utils/decorators.py" in _wrapper
  67.             return bound_func(*args, **kwargs)

File "/usr/local/lib/python3.5/dist-packages/django/utils/decorators.py" in _wrapped_view
  149.                     response = view_func(request, *args, **kwargs)

File "/usr/local/lib/python3.5/dist-packages/django/utils/decorators.py" in bound_func
  63.                 return func.__get__(self, type(self))(*args2, **kwargs2)

File "/usr/local/lib/python3.5/dist-packages/django/contrib/admin/options.py" in changelist_view
  1568.                 response = self.response_action(request, queryset=cl.get_queryset(request))

File "/usr/local/lib/python3.5/dist-packages/django/contrib/admin/options.py" in response_action
  1286.             response = func(self, request, queryset)

File "/usr/local/lib/python3.5/dist-packages/django/contrib/admin/actions.py" in delete_selected
  37.         queryset, opts, request.user, modeladmin.admin_site, using)

File "/usr/local/lib/python3.5/dist-packages/django/contrib/admin/utils.py" in get_deleted_objects
  172.     to_delete = collector.nested(format_callback)

File "/usr/local/lib/python3.5/dist-packages/django/contrib/admin/utils.py" in nested
  232.             roots.extend(self._nested(root, seen, format_callback))

File "/usr/local/lib/python3.5/dist-packages/django/contrib/admin/utils.py" in _nested
  216.             children.extend(self._nested(child, seen, format_callback))

File "/usr/local/lib/python3.5/dist-packages/django/contrib/admin/utils.py" in _nested
  218.             ret = [format_callback(obj)]

File "/usr/local/lib/python3.5/dist-packages/django/contrib/admin/utils.py" in format_callback
  145.                                    force_text(obj))

File "/usr/local/lib/python3.5/dist-packages/django/utils/encoding.py" in force_text
  76.                     s = six.text_type(s)

Exception Type: TypeError at /admin/wall/articles/
Exception Value: __str__ returned non-string (type Articles)

Answer 1

问题出在您的 Like 模型中。正如错误所说，该文章的__str__ 方法不是返回字符串，而是返回文章的实例。您应该确保实际返回一个字符串，例如self.articles.title。

这是一个删除问题的原因是因为删除一篇文章也会删除所有指向它的对象，并且 Django 有助于在确认页面上显示所有受影响的对象。

请注意，您的命名约定令人困惑。您应该为模型使用单数名称：文章、评论。