确定对象是否在一组模型中的外键？

Question

这是我的models.py：

class Blog(models.Model): 
    user = models.ForeignKey(User) 
    actualBlog = models.CharField(max_length=200) 

class BlogComments(models.Model): 
    user = models.ForeignKey(User) 
    blog = models.ForeignKey(Blog) 
    actualBlog = models.CharField(max_length=200) 

我通过了所有现有的博客列表，以我的模板。在我的模板中，我想查看request.user是否在评论博客的用户列表中。类似这样的：

{% for blog in allExistingBlogs %} 
    {% if request.user in blog.blogcomments_set.all %} 
     <p>you have already commented on this blog</p> 
    {% else %} 
     <p>you have not commented on this blog yet</p> 
    {% endif %} 
{% endfor %} 

但这并不起作用。我也试过

{% if request.user in blog.blogcomments_set.all.user %} 

但这也行不通。任何想法如何让它的工作？

Answer 1

装饰物体在你看来，你把它发送到您的模板之前：现在

def show_blogs(request): 
    all_blogs = Blog.objects.all() 
    blogs = [] 
    for blog in all_blogs: 
     blogs.append((blog, blog.blogcomments_set.all(), 
          blog.blogcomments_set.filter(user=request.user).count())) 
    return render(request, 'blogs.html', {'blogs': blogs}) 

，在你的模板：

{% for blog, comments, commented in blogs %} 
    {{ blog }} - {{ comments.count }} 
    {% if commented %} 
     You have already commented! 
    {% else %} 
     Would you like to comment? 
    {% endif %} 
{% endfor %} 

Answer 2

可以在Blog使用模型方法：

def _get_commenters(self): 
    commenters = self.blogcomments_set.values_list(user, flat=True) 
    return commenters 
commenters = property(_get_commenters) 

然后你只需要使用模板：

{% if request.user in blog.commenters %}