Django -> ListView -> get_context_data() -> Model.objects.filter(self.object)

Question

如何从ListView中获取每个模型对象？我有一个博客，我试着按照喜欢的评论数量来排序每个帖子的评论

views.py

class PostListView(ListView):
model = Post
template_name = 'blog/home.html'
context_object_name = 'posts'
ordering = ['-date_posted']
paginate_by = 5

def get_context_data(self, *args, **kwargs):
    com = Comment.objects.filter(post=self.object?) #<--- WHAT TO INPUT HERE?
    comment_list = com.annotate(like_count=Count('liked')).order_by('-like_count')

    #BELOW DOESN'T WORK. EVERY POST HAS THE SAME COMMENT LIST AS THE LATEST POST.. SEE PICTURE BELOW
    # posts = Post.objects.all()
    # for post in posts:
    #   com = Comment.objects.filter(post=post) #<--- what to input here
    #   comment_list = com.annotate(like_count=Count('liked')).order_by('-like_count')

    #BELOW DOESN'T WORK. EVERY POST HAS THE SAME COMMENT LIST AS THE LATEST POST.. SEE PICTURE BELOW
    # posts = Post.objects.all()
    # #for post in posts:
    #comment_list = post.comment_set.all().annotate(like_count=Count('liked')).order_by('-like_count')

    context = super(PostListView, self).get_context_data(*args, **kwargs)
    context['cats_menu'] = cats_menu
    context['c_form'] = c_form
    context['comment_list'] = comment_list
    return context

img链接-最新帖子

img链接-所有其他帖子复制最新帖子上的评论。

models.py

class Comment(models.Model):
user = models.ForeignKey(Profile, on_delete=models.CASCADE)
post = models.ForeignKey(Post, on_delete=models.CASCADE)
body = models.TextField(max_length=300)
updated = models.DateTimeField(auto_now=True)
created = models.DateTimeField(auto_now_add=True)
liked = models.ManyToManyField(Profile, blank=True, related_name='com_likes')

def __str__(self):
    return f"Comment:{self.user}-{self.post}-{self.id}"

def post_id(self):
    return self.post.id

def num_likes(self):
    return self.liked.all().count()

class CommentLike(models.Model):
user = models.ForeignKey(Profile, on_delete=models.CASCADE)
post = models.ForeignKey(Post, on_delete=models.CASCADE)
comment = models.ForeignKey(Comment, on_delete=models.CASCADE)
value = models.CharField(choices=LIKE_CHOICES, max_length=8)
updated = models.DateTimeField(auto_now=True)
created = models.DateTimeField(auto_now_add=True)

def __str__(self):
    return f" | CommentLike({self.user}-{self.comment}-{self.value})"

模板

{% for comment in comment_list %}

Answer 1

您可以使用动态滤波来指定查询集和预取对象

视图

class PostListView(ListView):
    model = Post
    template_name = "blog/home.html"
    context_object_name = "posts"
    ordering = ["-date_posted"]
    paginate_by = 5

    def get_queryset(self):
        return (
            super()
            .get_queryset()
            # Prefetch comment using a Prefetch object gives you more control
            .prefetch_related(
                Prefetch(
                    "comment",
                    # Specify the queryset to annotate and order by Count("liked")
                    queryset=Comment.objects.annotate(
                        like_count=Count("liked")
                    ).order_by("-like_count"),
                    # Prefetch into post.comment_list
                    to_attr="comment_list",
                )
            )
        )

模板

{% for post in posts %}
  {% for comment in post.comment_list %}
    {{ comment.like_count }}
  {% endfor %}
{% endfor %}