我想将模型的管理器写入模型类本身。
class Post(models.Model):
title = models.CharField(max_length=50)
slug = models.SlugField(max_length=50, blank=True, unique=True)
body = models.TextField(blank=True)
pub_date = models.DateTimeField(blank=True)
mod_date = models.DateTimeField(blank=True)
tags = models.ManyToManyField(Tag)
class Meta:
ordering = ['pub_date'] # Newest first
class Manager(models.Manager):
def by_slug(self, slug):
slug = slug.strip().lower()
return self.get(slug=slug)
objects = Manager()
def __unicode__(self):
return self.title
def save(self, *args, **kwargs):
self.slug = self.slug or generate_slug(self.title)
self.pub_date = self.pub_date or timezone.now()
self.mod_date = timezone.now()
return super(Post, self).save(*args, **kwargs)
但我收到以下错误:
Traceback (most recent call last):
File "C:\Users\niklas\Desktop\blog_project\manage.py", line 10, in <module>
execute_from_command_line(sys.argv)
File "C:\Python27\lib\site-packages\django-1.4.1-py2.7.egg\django\core\management\__init__.py", line 443, in execute_from_command_line
utility.execute()
File "C:\Python27\lib\site-packages\django-1.4.1-py2.7.egg\django\core\management\__init__.py", line 382, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "C:\Python27\lib\site-packages\django-1.4.1-py2.7.egg\django\core\management\base.py", line 196, in run_from_argv
self.execute(*args, **options.__dict__)
File "C:\Python27\lib\site-packages\django-1.4.1-py2.7.egg\django\core\management\base.py", line 231, in execute
self.validate()
File "C:\Python27\lib\site-packages\django-1.4.1-py2.7.egg\django\core\management\base.py", line 266, in validate
num_errors = get_validation_errors(s, app)
File "C:\Python27\lib\site-packages\django-1.4.1-py2.7.egg\django\core\management\validation.py", line 30, in get_validation_errors
for (app_name, error) in get_app_errors().items():
File "C:\Python27\lib\site-packages\django-1.4.1-py2.7.egg\django\db\models\loading.py", line 158, in get_app_errors
self._populate()
File "C:\Python27\lib\site-packages\django-1.4.1-py2.7.egg\django\db\models\loading.py", line 64, in _populate
self.load_app(app_name, True)
File "C:\Python27\lib\site-packages\django-1.4.1-py2.7.egg\django\db\models\loading.py", line 88, in load_app
models = import_module('.models', app_name)
File "C:\Python27\lib\site-packages\django-1.4.1-py2.7.egg\django\utils\importlib.py", line 35, in import_module
__import__(name)
File "C:\Users\niklas\Desktop\blog_project\blog\models.py", line 48, in <module>
class Post(models.Model):
File "C:\Python27\lib\site-packages\django-1.4.1-py2.7.egg\django\db\models\base.py", line 99, in __new__
new_class.add_to_class(obj_name, obj)
File "C:\Python27\lib\site-packages\django-1.4.1-py2.7.egg\django\db\models\base.py", line 219, in add_to_class
value.contribute_to_class(cls, name)
TypeError: Error when calling the metaclass bases
unbound method contribute_to_class() must be called with Manager instance as first argument (got ModelBase instance instead)
你能告诉我为什么会发生这个错误以及我想要做的事情是否可能?