python - 如何从模板调用模型函数？

Question

我正在从模板调用我的模型(Answer)函数isupvoted，同时迭代页面上显示的所有答案，以查看登录用户是否喜欢迭代回答。我的Answer和Upvote模型如下。

class Answer(models.Model):
    answer_text = models.TextField(max_length=5000)
    answer_author = models.ForeignKey(User, on_delete=models.CASCADE, related_name='ans_auth')
    question = models.ForeignKey(Question, on_delete=models.CASCADE)
    a_pub_date = models.DateTimeField('Date Answer Published')
    a_modified_date = models.DateTimeField('Date Answer Modified', null=True, blank=True)

    def __str__(self):
        return self.answer_text

    def isupvoted(self, request):
        counter = UpvoteAnswerMod.objects.filter(answer=self, upvote_user=request.user).count()
        print("upvote count: "+counter)
        return counter


class UpvoteAnswerMod(models.Model):
    answer = models.ForeignKey(Answer, on_delete=models.CASCADE)
    upvote_user = models.ForeignKey(User, on_delete=models.CASCADE)
    upvote_date = models.DateTimeField('Date Upvoted')

我正在调用如下函数

{% if answer.isupvoted == 1 %}
   <a class="upvote pressed" href="#" >Downvote</a>
{% else %}
   <a class="upvote" href="#" >Upvote</a>
{% endif %}

但是 answer.isupvoted 没有返回任何内容。如何获得点赞数？

Answer 1

在您的模型中，使用@property:

@property
def isupvoted(self, user):
    try:
        counter = UpvoteAnswerMod.objects.filter(answer=self, 
                                                 upvote_user=user).count()
        print("upvote count: "+counter)
        return counter
    except ObjectDoesNotExist as e:
        print("Not Found - {}".format(e))
        return 0