Question

我正在使用Django 1.3.1，我有以下模型：

class masterData(models.Model):
     uid = models.CharField(max_length=20,primary_key=True)

     class Meta:
          abstract = True;

class Type1(masterData):
     pass;

class Type2(masterData):
     pass;

现在，我正在尝试获取masterData的所有子类的列表。一世尝试过：

masterData.__subclasses__()

我发现上述非常有趣的事情就是它在 python manage.py shell 中完美运行，并且不完全可以正常工作在运行网络服务器时！

那么如何获取从抽象基类模型派生的模型列表？

谢谢：）

Answer 1

Metaclass for defining Abstract Base Classes (ABCs).

Use this metaclass to create an ABC. An ABC can be subclassed directly, and then acts as a mix-in 
class. You can also register unrelated concrete classes (even built-in classes) and unrelated ABCs 
as 'virtual subclasses' -- these and their descendants will be considered subclasses of the 
registering ABC by the built-in issubclass() function, but the registering ABC won't show up in 
their MRO (Method Resolution Order) nor will method implementations defined by the registering 
ABC be callable (not even via super()).

我没有太多使用过ABCMeta（实际上今天有点......）。您需要使用'issubclass（）'函数因为ABC不会出现在他们身上。

如果您使用了继承，子类（）将起作用。

>>> class foo(object):
...      pass
... 
>>> class bar(foo):
...      pass
... 
>>> a = bar()
>>> a.__class__.__mro__
(<class '__main__.bar'>, <class '__main__.foo'>, <type 'object'>)
>>> foo.__subclasses__()
[<class '__main__.bar'>]

在Django中列出ABC的子项

1 个答案: