ben ne var mptt

Question

kullanarak ManyRelatedManager nesne niteliğini erişme:

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) 

Ama " 'ManyRelatedManager' nesne hiçbir özelliği 'ni full_slug' vardır" bir hata alıyorum. Aslında sadece bir kategoriye ihtiyacım var, bu yüzden self.url = '%s/%s' % (self.category.all()[0].full_slug, self.slug)'u denedim, ancak yine de hatayı alıyorum.

Bunu çözmenin bir yolu var mı? Almak o çalışma tek yolu category=TreeForeignKey ile, ama bir TreeManyToManyField

Traceback gerekir: Bu hatayı alıyorsanız Basit bir ifadeyle

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' 

Answer 1

kodunuzda bakarsanız çünkü

category = TreeManyToManyField(Category, verbose_name='parent category', related_name='works') 

Çoktan-çok alan için Yani burada def kaydet (self, * args, ** kwargs): self.category: self.url = '% s /% s'% (self.category .full_slug, self.slug)

bana

category.full_slug vermek diyorsun Ve django kibarca orada için birden fazla kategori olmak ve örneğini Work ki sizi anlatıyor.

Bu nedenle, hangi self.category örneğinin istediğinizi bulmanız size kalmıştır.

örn. Buradan daha fazla

self.category.first().full_slug 

Okuma: Eğer kurtarmaya çalışıyor Çalışma örneğine ilgili herhangi Kategori örneklerini yoksa ders self.category.first Of https://docs.djangoproject.com/en/1.9/ref/models/relations/

() mevcut olmayabilir.

Çok ilgili bir notta, herhangi bir m2m modelini Work örneğinize ilişkilendirmeden önce Work örneğini kaydetmeniz gerekir.