This is my model. I have a many to one relationship.

class Course(models.Model):
    course_name = models.CharField(max_length=100)

class Coursegk(models.Model):
    question = models.CharField(max_length=1000)
    option_one = models.CharField(max_length=100)
    option_two = models.CharField(max_length=100)
    option_three = models.CharField(max_length=100)
    option_four = models.CharField(max_length=100)
    answer = models.CharField(max_length=100)
    courses = models.ForeignKey(Course, on_delete=models.CASCADE, related_name="display")

This is my views.py page

def showcourses(request):
    details = Course.objects.all()
    paginator = Paginator(details, 2)
    page_number = request.GET.get('page')
    page_obj = paginator.get_page(page_number)
    return render(request, 'index.html', {'data':page_obj})


def displaymcqpage(request, courses_id):
    displaymcq = Course.objects.get(id=courses_id)
    paginator = Paginator(displaymcq, 2)
    page_number = request.GET.get('page')
    page_obj = paginator.get_page(page_number)
    return render(request, 'coursegk.html', {'display':page_obj})

Now paginator is working fine for the index.html page. But when I go to coursegk.html page from index.html page I am getting "object of type 'Course' has no len()" error. How to use paginator for the displaymcqpage function?

CodePudding user response：

How to use paginator for the displaymcqpage function?

You don't. This is a detail view: you are showing details for a single Course object. Pagination means that you have a collection of objects, and you show a subset of these, but here there is a single Course determined by the courses_id parameter, hence pagination makes no sense.

You can paginate the Coursegk objects related to that Course with:

def displaymcqpage(request, courses_id):
    displaymcq = Course.objects.get(id=courses_id)
    paginator = Paginator(displaymcq.display.all(), 2)
    page_number = request.GET.get('page')
    page_obj = paginator.get_page(page_number)
    return render(request, 'coursegk.html', {'dta': displaymcq, 'coursegks': page_obj})

and here we thus paginate the related Coursegk objects, but then we do not paginate the Course records.

Note: It is often better to use get_object_or_404(…) [Django-doc], then to use .get(…) [Django-doc] directly. In case the object does not exists, for example because the user altered the URL themselves, the get_object_or_404(…) will result in returning a HTTP 404 Not Found response, whereas using .get(…) will result in a HTTP 500 Server Error.