Using "in" operator in Django template not working as expected - django

Question

Could really use help figuring out what I'm misunderstanding about the following: I'm using the built-in "in" operator to check if a user (standard user model) is in a queryset of Board members.
This is the Board member model:
class BoardMembers(models.Model):
board = models.ForeignKey(Board, related_name="memberships", blank=True)
user = models.ForeignKey(User,related_name='user_boards', blank=True)
member_role = models.CharField(choices=MEMBER_ROLES, max_length=100, blank=True)
def __str__(self):
return self.user.username
Here is the view I'm using:
class ViewBoard(SelectRelatedMixin, generic.DetailView):
model = models.Board
select_related = ("user",)
template_name = 'board/view_board.html'
def get_context_data(self, **kwargs):
context = super(ViewBoard, self).get_context_data(**kwargs)
context['boardmembers_list'] = BoardMembers.objects.filter(board__slug=self.kwargs['slug'])
return context
And this is the html part I'm struggling with:
{% if user in boardmembers_list %}
<h1>HEY, {{ user.username }}, YOU'RE ALREADY A MEMBER!</h1>
{% else %}
<a class="btn btn-primary" href="{% url 'board:join_board' slug=board.slug pk=board.pk %}">Join this Board</a>
{% endif %}
I tested to see if individually the objects could be retrieved in the template and both the user and the boardmembers_list show up correctly.
From the docs it looks like this should be a relatively straightforward thing to do. Can anyone tell me where I'm going wrong or what I'm misunderstanding about how these operators work?

Answer 1

I think its better to decide if the user is in board or not in the View, instead of template.
class ViewBoard(SelectRelatedMixin, generic.DetailView):
...
def get_context_data(self, **kwargs):
board_mem_list = BoardMembers.objects.filter(board__slug=self.kwargs['slug'])
context = super(ViewBoard, self).get_context_data(**kwargs)
context['boardmembers_list'] = board_mem_list
context['user_in_board'] = board_mem_list.filter(user=self.request.user).exists() # this will check if user is already in boardmemberlist
return context
In template:
{% if user_in_board %}
<h1>HEY, {{ user.username }}, YOU'RE ALREADY A MEMBER!</h1>
{% else %}
<a class="btn btn-primary" href="{% url 'board:join_board' slug=board.slug pk=board.pk %}">Join this Board</a>
{% endif %}
And you are trying to search userin boardmemebers_list, and it won't work because user is a User model instance and boardmemebers_list is a queryset of BoardMember model where user is just a field of that model.