我试图将我的模型之一中的字段限制为特定组的所有用户的选择。另一个字段具有所有注册用户的选择。在外壳中可以正常工作：
>>> from django.contrib.auth.models import User, Group
>>> all_users = User.objects.all()
>>> all_users
<QuerySet [<User: somedude>, <User: test>, <User: testma>]>
>>> tm_users = User.objects.filter(groups__name='Testmanager')
>>> tm_users
<QuerySet [<User: somedude>, <User: testma>]>
但是，如果我将相同的代码放入模型中：
class TestPlan(models.Model):
all_users = User.objects.all()
all_user_choices = ((x.username, x.get_full_name()) for x in all_users)
tm_users = User.objects.filter(groups__name='Testmanager')
tm_user_choices = ((x.username, x.get_full_name()) for x in tm_users)
tp_title = models.CharField(max_length=200, verbose_name='Title')
tp_manager = models.CharField(max_length=100, blank=True,
verbose_name='Test Manager',
choices=tm_user_choices)
tp_tester = models.CharField(max_length=100, blank=True,
verbose_name='Tester',
choices=all_user_choices)
def __str__(self):
return f'{self.tp_title}'
我得到以下内容（对我而言）没有帮助（堆栈）：
O:\somedude\Documents\Python\Django\testcases>manage.py makemigrations
Traceback (most recent call last):
File "O:\somedude\Documents\Python\Django\testcases\manage.py", line 15, in <module>
execute_from_command_line(sys.argv)
File "C:\Program Files\Python36\lib\site-packages\django\core\management\__init__.py", line 381, i
n execute_from_command_line
utility.execute()
File "C:\Program Files\Python36\lib\site-packages\django\core\management\__init__.py", line 357, i
n execute
django.setup()
File "C:\Program Files\Python36\lib\site-packages\django\__init__.py", line 24, in setup
apps.populate(settings.INSTALLED_APPS)
File "C:\Program Files\Python36\lib\site-packages\django\apps\registry.py", line 112, in populate
app_config.import_models()
File "C:\Program Files\Python36\lib\site-packages\django\apps\config.py", line 198, in import_mode
ls
self.models_module = import_module(models_module_name)
File "C:\Program Files\Python36\lib\importlib\__init__.py", line 126, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
File "<frozen importlib._bootstrap>", line 994, in _gcd_import
File "<frozen importlib._bootstrap>", line 971, in _find_and_load
File "<frozen importlib._bootstrap>", line 955, in _find_and_load_unlocked
File "<frozen importlib._bootstrap>", line 665, in _load_unlocked
File "<frozen importlib._bootstrap_external>", line 678, in exec_module
File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
File "O:\somedude\Documents\Python\Django\testcases\testman\models.py", line 68, in <module>
class TestPlan(models.Model):
File "O:\somedude\Documents\Python\Django\testcases\testman\models.py", line 70, in TestPlan
tm_users = User.objects.filter(groups__name='Testmanager')
File "C:\Program Files\Python36\lib\site-packages\django\db\models\manager.py", line 82, in manage
r_method
return getattr(self.get_queryset(), name)(*args, **kwargs)
File "C:\Program Files\Python36\lib\site-packages\django\db\models\query.py", line 844, in filter
return self._filter_or_exclude(False, *args, **kwargs)
File "C:\Program Files\Python36\lib\site-packages\django\db\models\query.py", line 862, in _filter
_or_exclude
clone.query.add_q(Q(*args, **kwargs))
File "C:\Program Files\Python36\lib\site-packages\django\db\models\sql\query.py", line 1263, in ad
d_q
clause, _ = self._add_q(q_object, self.used_aliases)
File "C:\Program Files\Python36\lib\site-packages\django\db\models\sql\query.py", line 1287, in _a
dd_q
split_subq=split_subq,
File "C:\Program Files\Python36\lib\site-packages\django\db\models\sql\query.py", line 1164, in bu
ild_filter
lookups, parts, reffed_expression = self.solve_lookup_type(arg)
File "C:\Program Files\Python36\lib\site-packages\django\db\models\sql\query.py", line 1028, in so
lve_lookup_type
_, field, _, lookup_parts = self.names_to_path(lookup_splitted, self.get_meta())
File "C:\Program Files\Python36\lib\site-packages\django\db\models\sql\query.py", line 1365, in na
mes_to_path
if field.is_relation and not field.related_model:
File "C:\Program Files\Python36\lib\site-packages\django\utils\functional.py", line 37, in __get__
res = instance.__dict__[self.name] = self.func(instance)
File "C:\Program Files\Python36\lib\site-packages\django\db\models\fields\related.py", line 94, in
related_model
apps.check_models_ready()
File "C:\Program Files\Python36\lib\site-packages\django\apps\registry.py", line 137, in check_mod
els_ready
raise AppRegistryNotReady("Models aren't loaded yet.")
django.core.exceptions.AppRegistryNotReady: Models aren't loaded yet.
O:\somedude\Documents\Python\Django\testcases>
当我执行User.objects.all（）时，它可以工作，但是当我尝试按组过滤用户时，它就会失败。我真的不知道我在做什么错。这是错误还是功能？
最佳答案
您可能必须重写save方法和clean方法：
from django.core.exceptions import ValidationError
def clean(self):
if self.tp_manager and not self.tp_manager.groups.filter(name='Testmanager').exists():
raise ValidationError({'tp_manager': 'ValidationError Msg'})
def save(self, *args, **kwargs):
self.full_clean()
return super().save(*args, **kwargs)
Django文件：https://docs.djangoproject.com/en/2.0/ref/models/instances/#django.db.models.Model.clean
否则，您可以使用ModelForm并编写一个清理函数来实施验证检查。
如果要使用表格，则可以轻松处理动态选择。
class TestPlanForm(forms.ModelForm):
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
tm_users = User.objects.filter(groups__name='Testmanager')
tm_user_choices = ((x.username, x.get_full_name()) for x in tm_users)
self.fields['tp_manager'].choices = tm_user_choices
class Meta:
model = TestPlan
fields = '__all__'