如何在 Django 中呈现外键字段

Question

期望的结果：当我呈现轮询器及其相关注释时我还想呈现 Vote 为轮询器选择的用户及其评论（注意：用户只有在对该轮询器投票后才能发表评论）。

旁注：用户可以对投票者投一票，并 post 对投票者发表评论。他只有事先投票才能发表评论。

# Models

class Poller(models.Model):
    poller_id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    created_on = models.DateTimeField(auto_now_add=True)
    created_by = models.ForeignKey(Account, on_delete=models.CASCADE)
    poller_text = models.CharField(max_length=333)
    poller_choice_one = models.CharField(max_length=20)
    poller_choice_two = models.CharField(max_length=20)


class Vote(models.Model):
    poller = models.ForeignKey(Poller, on_delete=models.CASCADE, related_name='vote')
    user = models.ForeignKey(Account, on_delete=models.CASCADE)
    created_on = models.DateTimeField(auto_now_add=True)
    poller_choice_one_vote = models.BooleanField(default=False)
    poller_choice_two_vote = models.BooleanField(default=False)

    def __str__(self):
        return f'Vote by {self.user}'


class Comment(models.Model):
    poller = models.ForeignKey(Poller, on_delete=models.CASCADE, related_name='PollerComment')
    user = models.ForeignKey(Account, on_delete=models.CASCADE)
    created_on = models.DateTimeField(auto_now_add=True)
    comment = models.TextField(max_length=350)
    flag_count = models.IntegerField(default=0)
    upvote_count = models.IntegerField(default=0)
    downvote_count = models.IntegerField(default=0)

# View

@require_GET
def render_single_poller(request, poller_id):

    # Retrieve comments associated to the Poller
    comments_qs = PollerComment.objects.filter(poller_id=poller_id)

context = {
        'comments_qs': comments_qs,
    }
    return render(request, 'pollboard/single_poller.html', context)

我试过像这样通过模板过滤器来做到这一点：

# pollboard_tags.py

@register.filter(name='get_vote')
def get_voted(self):
    self.vote_made = 'Test'
    print(self.vote.poller_choice_one_vote)
    if self.vote.poller_choice_one_vote:
        self.vote_made = 'One'
    else:
        self.vote_made = 'Two'
    return self.vote_made

# template

<div class="commentors-poller-choice">{{ comment|get_vote }}</div>

投掷

RelatedObjectDoesNotExist at /poller/68c725eb-277e-4b5b-a61b-b4a02bf5e854/ PollerComment has no vote.

恐怕我已经把这里的事情复杂化了。我希望有一个更直接的解决方案，比如 idk 通过渲染所需的信息扩展评论查询集？

Answer 1

如果用户只能对轮询器投票一次，您可以过滤：

@register.filter(name='get_vote')
def get_voted(self):
    vote = Vote.objects.get(poller=self.poller, user=self.user)
    return 'One' if vote.poller_choice_one_vote else 'Two'

如何在 Django 中呈现外键字段

How to render a foreign key field in Django

django

django-models

django-queryset