python - AttributeError at/'tuple' 对象没有属性 '_meta'

Question

我在这段代码的第二行在 Django 中遇到上述错误:

    survey = Survey.objects.get_or_create(organisation=organisation)
    form = SurveyForm(instance=survey)

这是我的表格:

class SurveyForm(forms.ModelForm):
    class Meta:
        model = Survey
        exclude = ['id']
        widgets = {
            'user' : forms.HiddenInput(),
            'organisation' : forms.HiddenInput(),
            'responsibleSecurityOfficer' : forms.TextInput(attrs={'class' : 'form-control'}),
            'responsibleSecurityOfficerJobTitle'  : forms.TextInput(attrs={'class' : 'form-control'}),
            'size' : forms.Select(attrs={'class' : 'form-control'},
                                  choices=SIZE_CHOICES),
            'baseInfoSecurity' : forms.Select(attrs={'class' : 'form-control'}),
            'pciCompliance'  : forms.Select(attrs={'class' : 'form-control'}),
            'hipaaCompliance' :  forms.Select(attrs={'class' : 'form-control'}),
            'internationalCompliance' : forms.Select(attrs={'class' : 'form-control'}),
            'country' : forms.TextInput(attrs={'class' : 'form-control'}),
            'drPlan' : forms.Select(attrs={'class' : 'form-control'}),
        }

我真的不明白为什么它不起作用而且我没有看到任何错误的逗号(这似乎是基于类似帖子的普遍问题)。欢迎任何帮助。

编辑

回溯

File "/home/henry/Documents/Sites/Development/dashpliant/env/local/lib/python2.7/site-packages/django/core/handlers/exception.py" in inner
  41.             response = get_response(request)

File "/home/henry/Documents/Sites/Development/dashpliant/env/local/lib/python2.7/site-packages/django/core/handlers/base.py" in _get_response
  187.                 response = self.process_exception_by_middleware(e, request)

File "/home/henry/Documents/Sites/Development/dashpliant/env/local/lib/python2.7/site-packages/django/core/handlers/base.py" in _get_response
  185.                 response = wrapped_callback(request, *callback_args, **callback_kwargs)

File "/home/henry/Documents/Sites/Development/dashpliant/env/local/lib/python2.7/site-packages/django/views/generic/base.py" in view
  68.             return self.dispatch(request, *args, **kwargs)

File "/home/henry/Documents/Sites/Development/dashpliant/env/local/lib/python2.7/site-packages/django/contrib/auth/mixins.py" in dispatch
  92.         return super(PermissionRequiredMixin, self).dispatch(request, *args, **kwargs)

File "/home/henry/Documents/Sites/Development/dashpliant/env/local/lib/python2.7/site-packages/django/views/generic/base.py" in dispatch
  88.         return handler(request, *args, **kwargs)

File "/home/henry/Documents/Sites/Development/dashpliant/dashpliant/views.py" in get
  38.         form = SurveyForm(instance=survey)

File "/home/henry/Documents/Sites/Development/dashpliant/env/local/lib/python2.7/site-packages/django/forms/models.py" in __init__
  297.             object_data = model_to_dict(instance, opts.fields, opts.exclude)

File "/home/henry/Documents/Sites/Development/dashpliant/env/local/lib/python2.7/site-packages/django/forms/models.py" in model_to_dict
  87.     opts = instance._meta

Exception Type: AttributeError at /survey/
Exception Value: 'tuple' object has no attribute '_meta'

Answer 1

get_or_create返回 (instance, created) 的元组，其中第二个元素是一个 bool 值，显示操作是否导致创建新项目。您应该单独捕获这些，而不是将整个内容传递给表单。您可以使用 _ 表示您不关心 created 值。

survey, _ = Survey.objects.get_or_create(organisation=organisation)
form = SurveyForm(instance=survey)