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python - NoneType 对象不可调用 django admin

问题描述

我在 django admin 中有一个应用程序，我正在尝试进行一些验证，Transaction模型及其 2 个模型的父级，FamilyGroup以及FamilMember

class Transaction(models.Model):
    chp_reference = models.CharField(max_length=50, unique=True)
    number_of_family_group = models.PositiveSmallIntegerField( null=True)

class FamilyGroup(models.Model):
    name = models.CharField(max_length=10, choices=name_choices)
    transaction =models.ForeignKey(Transaction,on_delete=models.CASCADE,related_name='family_groups')
    
class FamilyMember(models.Model):
    transaction = models.ForeignKey(Transaction, on_delete=models.CASCADE)
    family_group = models.ForeignKey(FamilyGroup,
                                     on_delete=models.CASCADE,
                                     null=True,
                                      blank=True, related_name='family_members')
    name = models.CharField(max_length=100, null=True, blank=True)
    date_of_birth = models.DateField(null=True, blank=True)

我试图在这样的transaction模型中进行客户验证

@property
def clean(self):
    b = FamilyGroup.objects.filter(transaction__id=self.id).count()
    if self.number_of_family_group != b:
        raise ValidationError('worng family')

当我试图这样做时，我得到了一个错误NoneType object is not callable

追溯：

Traceback (most recent call last):
  File "E:\15-12\venv\lib\site-packages\django\core\handlers\exception.py", line 34, in inner
    response = get_response(request)
  File "E:\15-12\venv\lib\site-packages\django\core\handlers\base.py", line 115, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "E:\15-12\venv\lib\site-packages\django\core\handlers\base.py", line 113, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "E:\15-12\venv\lib\site-packages\django\contrib\admin\options.py", line 607, in wrapper
    return self.admin_site.admin_view(view)(*args, **kwargs)
  File "E:\15-12\venv\lib\site-packages\django\utils\decorators.py", line 130, in _wrapped_view
    response = view_func(request, *args, **kwargs)
  File "E:\15-12\venv\lib\site-packages\django\views\decorators\cache.py", line 44, in _wrapped_view_func
    response = view_func(request, *args, **kwargs)
  File "E:\15-12\venv\lib\site-packages\django\contrib\admin\sites.py", line 231, in inner
    return view(request, *args, **kwargs)
  File "E:\15-12\venv\lib\site-packages\django\contrib\admin\options.py", line 1641, in change_view
    return self.changeform_view(request, object_id, form_url, extra_context)
  File "E:\15-12\venv\lib\site-packages\django\utils\decorators.py", line 43, in _wrapper
    return bound_method(*args, **kwargs)
  File "E:\15-12\venv\lib\site-packages\django\utils\decorators.py", line 130, in _wrapped_view
    response = view_func(request, *args, **kwargs)
  File "E:\15-12\venv\lib\site-packages\django\contrib\admin\options.py", line 1522, in changeform_view
    return self._changeform_view(request, object_id, form_url, extra_context)
  File "E:\15-12\venv\lib\site-packages\django\contrib\admin\options.py", line 1558, in _changeform_view
    form_validated = form.is_valid()
  File "E:\15-12\venv\lib\site-packages\django\forms\forms.py", line 180, in is_valid
    return self.is_bound and not self.errors
  File "E:\15-12\venv\lib\site-packages\django\forms\forms.py", line 175, in errors
    self.full_clean()
  File "E:\15-12\venv\lib\site-packages\django\forms\forms.py", line 378, in full_clean
    self._post_clean()
  File "E:\15-12\venv\lib\site-packages\django\forms\models.py", line 404, in _post_clean
    self.instance.full_clean(exclude=exclude, validate_unique=False)
  File "E:\15-12\venv\lib\site-packages\django\db\models\base.py", line 1207, in full_clean
    self.clean()
TypeError: 'NoneType' object is not callable
[02/Feb/2021 18:47:46] "POST /calculator/transaction/31/change/ HTTP/1.1" 500 143966

标签： pythondjango

解决方案

添加related_name='something'到 model FamilyMember，因此您可以像这样重写您的clean方法：

def clean(self):
    b = self.something.count()
    if self.number_of_family_group != b:
        raise ValidationError('worng family')

还记得从你的方法中删除 @property装饰器。clean

希望能解决你的问题。

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