模型Mixin中的Django GenericRelation

Question

我有mixin和型号:

class Mixin(object):
    field = GenericRelation('ModelWithGR')

class MyModel(Mixin, models.Model):
   ...

但是django不会把GenericRelation场变成GenericRelatedObjectManager:

>>> m = MyModel()
>>> m.field
<django.contrib.contenttypes.fields.GenericRelation>

当我将字段放入模型本身或抽象模型时 - 它工作正常:

class MyModel(Mixin, models.Model):
   field = GenericRelation('ModelWithGR')

>>> m = MyModel()
>>> m.field
<django.contrib.contenttypes.fields.GenericRelatedObjectManager at 0x3bf47d0>

我怎样才能GenericRelation在mixin中使用？

Answer 1

您始终可以从中继承Model并使其成为抽象而不是从中继承object.Python的mro会解决所有问题.像这样:

class Mixin(models.Model):
    field = GenericRelation('ModelWithGR')

    class Meta:
        abstract = True

class MyModel(Mixin, models.Model):
    ...