python - 将 InlineField 添加到 ClusterableModel 不起作用

Question

我有一个名为 EventDetail 的 Page 类，它又保存多条消息(通过 cronjob 发送出去)。这是按照此处的文档所示完成的: https://docs.wagtail.io/en/v2.5.1/reference/pages/panels.html?highlight=available%20panel%20types#inline-panels

问题是我还希望能够将多个文件附加到每条消息中。但现在我不再参加 Page 类(class)了，我无法让它工作。我在其他论坛帖子上读到，可以通过将 InlinePanel 保存为 ClusterableModel 的模型来实现这一点，但我无法让它工作。执行此操作时，我在访问页面时收到以下信息:

FieldError at /admin/message/eventdetailmessage/create/
Unknown field(s) (files) specified for EventDetailMessage

我的代码:

class Message(models.Model):
"""
    An abstract model of messages connected to an eventdetail
"""

title = models.CharField(max_length=255, blank=True)
content = models.TextField()
send_time = models.DateTimeField(verbose_name=_("Message send time"))
sent = models.BooleanField(default=False)

@property
def edit_link(self):
    return self.url_helper.get_action_url("edit", self.id)

@property
def delete_link(self):
    return self.url_helper.get_action_url("delete", self.id)

@property
def create_link(self):
    return f"{self.url_helper.get_action_url('create')}?id={self.event_detail.id}"

panels = [FieldPanel("title"), FieldPanel("content"), FieldPanel("send_time")]

class Meta:
    abstract = True

class EventDetailMessage(ClusterableModel, Orderable, Message):
"""
    The actual implementation. Done like this in case we want do use
    wagtails built in functionality for creating on the fly. 
"""

event_detail = ParentalKey(
    EventDetail, on_delete=models.CASCADE, related_name="messages"
)

panels = [FieldPanel("event_detail"), InlinePanel("files")] + Message.panels

def __init__(self, *args, **kwargs):
    from .wagtail_hooks import MessageDataAdmin

    self.url_helper = MessageDataAdmin().url_helper
    super().__init__(*args, **kwargs)

def __str__(self):
    return self.title


class File(models.Model):
    file = models.FileField()
    message = ParentalKey(
        EventDetailMessage, on_delete=models.CASCADE, related_name="files"
    )

    panels = [FieldPanel("file")]

Answer 1

我找到了! File类下的ParentalKey定义需要用引号定义，否则不起作用，应该是这样的:

message = ParentalKey(
    "message.EventDetailMessage", on_delete=models.CASCADE, related_name="files"
)

但是我仍然不确定这是为什么，有人可以解释一下吗？