Question

我得到了什么：

class Category(MPTTModel):
    name = models.CharField(max_length=50, unique=True)
    slug = models.SlugField(unique=True)
    full_slug = models.CharField(max_length=256, null=True, blank=True)
    parent = TreeForeignKey('self', null=True, blank=True, related_name='children', db_index=True)

class Work(models.Model):
    title = models.CharField(max_length=128, unique=True)
    slug = models.SlugField(max_length=128, unique=True)    
    category = TreeManyToManyField(Category, verbose_name='parent category', related_name='works')
    url = models.CharField(max_length=256, null=True, blank=True)

    def save(self, *args, **kwargs):
        if self.category:
            self.url = '%s/%s' % (self.category.full_slug, self.slug)
        else:
            self.url = '%s' % self.slug
        super(Work, self).save(*args, **kwargs)

但我收到错误＆＃34;＆＃39; ManyRelatedManager＆＃39;对象没有属性＆＃39; full_slug＆＃39;＆＃34;。实际上我只需要一个类别，所以我尝试了self.url = '%s/%s' % (self.category.all()[0].full_slug, self.slug)，但我还是得到了错误。

那么，有没有办法解决这个问题？我使用它的唯一方法是category=TreeForeignKey，但我需要一个TreeManyToManyField

回溯：

Environment:


Request Method: POST
Request URL: http://127.0.0.1:8000/admin/website/work/1/change/

Django Version: 1.9.5
Python Version: 3.5.1
Installed Applications:
['django.contrib.admin',
 'django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.messages',
 'django.contrib.staticfiles',
 'mptt',
 'django_mptt_admin',
 'website']
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.auth.middleware.SessionAuthenticationMiddleware',
 'django.contrib.messages.middleware.MessageMiddleware',
 'django.middleware.clickjacking.XFrameOptionsMiddleware']



Traceback:

File "E:\web\env\lib\site-packages\django\core\handlers\base.py" in get_response
  149.                     response = self.process_exception_by_middleware(e, request)

File "E:\web\env\lib\site-packages\django\core\handlers\base.py" in get_response
  147.                     response = wrapped_callback(request, *callback_args, **callback_kwargs)

File "E:\web\env\lib\site-packages\django\contrib\admin\options.py" in wrapper
  541.                 return self.admin_site.admin_view(view)(*args, **kwargs)

File "E:\web\env\lib\site-packages\django\utils\decorators.py" in _wrapped_view
  149.                     response = view_func(request, *args, **kwargs)

File "E:\web\env\lib\site-packages\django\views\decorators\cache.py" in _wrapped_view_func
  57.         response = view_func(request, *args, **kwargs)

File "E:\web\env\lib\site-packages\django\contrib\admin\sites.py" in inner
  244.             return view(request, *args, **kwargs)

File "E:\web\env\lib\site-packages\django\contrib\admin\options.py" in change_view
  1440.         return self.changeform_view(request, object_id, form_url, extra_context)

File "E:\web\env\lib\site-packages\django\utils\decorators.py" in _wrapper
  67.             return bound_func(*args, **kwargs)

File "E:\web\env\lib\site-packages\django\utils\decorators.py" in _wrapped_view
  149.                     response = view_func(request, *args, **kwargs)

File "E:\web\env\lib\site-packages\django\utils\decorators.py" in bound_func
  63.                 return func.__get__(self, type(self))(*args2, **kwargs2)

File "C:\Python35\Lib\contextlib.py" in inner
  30.                 return func(*args, **kwds)

File "E:\web\env\lib\site-packages\django\contrib\admin\options.py" in changeform_view
  1378.                 self.save_model(request, new_object, form, not add)

File "E:\web\env\lib\site-packages\django\contrib\admin\options.py" in save_model
  991.         obj.save()

File "E:\web\website\models.py" in save
  63.             self.url = '%s/%s' % (self.category.full_slug, self.slug)

Exception Type: AttributeError at /admin/website/work/1/change/
Exception Value: 'ManyRelatedManager' object has no attribute 'full_slug'

如何使用mptt访问ManyRelatedManager对象属性

0 个答案: