Number of Items per month works in CreateView, but not in TemplateView-CodePudding

My goal: get Count of items per month displayed in my template, i.e.: May 2021 - 5, June 2021 - 10, Sep 2021 - 3, Oct 2021 - 2, etc

What I've done. I first created a test-project and my Index view inherited from CreateView (needed that for a form). Everything worked fine. However, in my main project my IndexView is inherited from django's TemplateView, and with the same code it shows like this: Sep 2021 - 1, Sep 2021 - 1, Oct 2021 - 1, Oct 2021 - 1, Oct 2021 - 1... you get the point. So, for some reason, it sees every item as a separate date without trying to aggregate them.

So the difference-maker has to be the inheritance from different views in django, however, in my main project, I cannot make my index view inherit from CreateView. Also, I'm still new to Django and would really appreciate all the help I can get. It took me a lot of effort to figure it out up until this point.

Here's my working code (in the test-project):

models.py

class Movie(models.Model):
    title = models.CharField('Movie name', max_length=100)
    gross = models.IntegerField('Gross', help_text='Worldwide, in dollars.')
    release_date = models.DateField('Date of release', blank=True, null=True)

    def __str__(self):
        return self.title

views.py (pay attention to context['per_month'] line)

class IndexView(CreateView):
    form_class = CreateMovieForm
    template_name = 'home/index.html'
    success_url = '/'

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        # per_month = queryset of dictionaries: month   number of movies in each month
        context['per_month'] = Movie.objects.annotate(
            month=TruncMonth('release_date')).values('month').annotate(c=Count('id')).values('month', 'c')
        context['movies'] = Movie.objects.all()
        return context

forms.py (not sure if it's relevant here, but just in case)

class CreateMovieForm(forms.ModelForm):
    class Meta:
        model = Movie
        fields = '__all__'

        widgets = {'release_date': DateInput(attrs={'value': timezone.now().date})}

index.html

{% for month in per_month %}
    <ul>
        <li>
            {{ month.month|date:"M Y" }} - {{ month.c }}
        </li>
    </ul>
{% endfor %}

Output:

Aug 2021 - 2 Sep 2021 - 1 Oct 2021 - 3

Here's my NOT working code (main project):

models.py

class Item(models.Model):
    title = models.CharField(max_length=200)
    author = models.ForeignKey(User, on_delete=models.CASCADE)
    assigned_to = models.ManyToManyField(User)
    date_posted = models.DateTimeField(auto_now_add=True)
    deadline_date = models.DateField(null=True)

Note: I tried experimenting with both: date_posted and deadline_date (in case the problem was DatetimeField, as opposed to DateField), but it didn't help.

views.py (same context['per_month'] line)

class IndexView(LoginRequiredMixin, TemplateView):
    template_name = 'bugtracker/main.html'

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)

        # per_month = queryset of dictionaries: month   number of movies in each month
        context['per_month'] = Item.objects.annotate(
            month=TruncMonth('date_posted')).values('month').annotate(c=Count('id')).values('month', 'c')

index.html (same as above)

Output:

Aug 2021 -1 Aug 2021 -1 Oct 2021 - 1 Oct 2021 - 1 Oct 2021 - 1 Oct 2021 - 1

CodePudding user response：

You should add a .order_by(…) to force grouping by, so:

context['per_month'] = Item.objects.values(
    month=TruncMonth('date_posted')
).annotate(c=Count('id')).order_by('month')