CODEWITHSUNDEEP
pythondjango
khashashin
khashashin

Reputation: 1127

Getting additional data inside class based django view

Im following Mozilla Django Tutorial and created following view:

view.py

class BookListView(generic.ListView):
    model = Book
    queryset = Book.objects.filter(title__icontains='war')[:5] # Get 5 books containing the title war
    context_object_name = 'book_list'   # your own name for the list as a template variable
    template_name = 'catalog/index.html'  # Specify your own template name/location
    paginate_by = 3

I have reorganized files in my project and I want to display additional information on my template. I tried to do that using get_context_data(self, **kwargs): but then I get only that what I have defined inside this method.

Changed to:

class BookListView(generic.ListView):
    model = Book
    #queryset = Book.objects.filter(title__icontains='war')[:5] # Get 5 books containing the title war
    #context_object_name = 'book_list'   # your own name for the list as a template variable
    template_name = 'catalog/index.html'  # Specify your own template name/location
    paginate_by = 3

    def get_context_data(self, **kwargs):
        # Call the base implementation first to get the context
        context = super(BookListView, self).get_context_data(**kwargs)

        display_books = Book.objects.filter(title__icontains='war')[:5]

        # Generate counts of some of the main objects
        num_books=Book.objects.all().count()
        num_instances=BookInstance.objects.all().count()

        # Available books (status = 'a')
        num_instances_available=BookInstance.objects.filter(
                                                status__exact='a').count()
        num_authors=Author.objects.count()  # The 'all()' is implied by default.          

        # Create any data and add it to the context
        context = {
           'display_books':display_books,
           'num_books':num_books,
           'num_instances':num_instances,
           'num_instances_available':num_instances_available,
           'num_authors':num_authors
        }
        return context

This way is my pagination doesn't work.

Upvotes: 0

Views: 179

Answers (2)

MaximeK
MaximeK

Reputation: 2061

When you do :

context = super(BookListView, self).get_context_data(**kwargs)

You get the context, but you re-assign context at the end :

context = {
       'display_books':display_books,
       'num_books':num_books,
       'num_instances':num_instances,
       'num_instances_available':num_instances_available,
       'num_authors':num_authors
    }

what you need to do is add element to the dict:

context["display_books"] = display_books
context["num_books"] = num_books
context["num_instances"] = num_instances
context["num_instances_available"] = num_instances_available
context["num_authors"] = num_authors

Upvotes: 0

Alasdair
Alasdair

Reputation: 308779

The problem is that you replace the context dict from the super() call with a brand new dictionary.

def get_context_data(self, **kwargs):

    context = super(BookListView, self).get_context_data(**kwargs)
    ...
    context = {
       'display_books':display_books,
       'num_books':num_books,
       'num_instances':num_instances,
       'num_instances_available':num_instances_available,
       'num_authors':num_authors
    }
    return context

You should update the existing dictionary instead:

def get_context_data(self, **kwargs):
    context = super(BookListView, self).get_context_data(**kwargs)
    ...
    context['display_books'] = display_books
    context['num_books'] = num_books
    context['num_instances'] = num_instances
    context['num_instances_available'] = num_instances_available
    context['num_authors'] = num_authors
    return context

Upvotes: 1

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