Django分页依赖于排序

Question

我有以下模型（简化）：

class Post(models.Model):
    title = models.CharField(max_length=20)
    date_created = models.DateTimeField(auto_now=True)

    class Meta:
        ordering = ('-date_created',) # note the "reverse" ordering here

，然后是我基于generic.DetailView的自定义DetailView：

class PostDetailView(generic.DetailView):
    queryset = Post.objects.all()

最后是以下模板：

{% with object.get_previous_by_date_created as prev %}
    {% if prev %}
    <a class="nav-link-prev"
       href="{% url "blog:post_detail" pk=prev.id %}">Previous</a>
    {% endif %}
{% endwith %}

{% with object.get_next_by_date_created as next %}
    {% if next %}
    <a class="nav-link-next"
       href="{% url "blog:post_detail" pk=next.id %}">Next</a>
    {% endif %}
{% endwith %}

我以这种方式实现的分页工作，但由于反向排序（即-date_created）字段，其上一个/下一个标签放错了位置。换句话说，我的模板输出“上一个”应该是“下一个”，反之亦然。如果我删除 - 登录 ordering = ('-date_created',) 它将正常工作，但这不是我希望在我的网站上的顺序。

是否有一种简单而惯用的方法来解决这种不当行为？我错过了什么？

Answer 1

添加

ordering = ['-date_created']

或

ordering = Post._meta.ordering

致PostListView

Answer 2

我走这条路并且能够解决问题：

class PostDetailView(generic.DetailView):
    model = Post

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

        next = Post.objects.filter(pk__lt=self.object.pk).order_by('-pk')[:1]
        prev = Post.objects.filter(pk__gt=self.object.pk).order_by('pk')[:1]
        if prev:
            context['prev'] = prev[0]
        if next:
            context['next'] = next[0]

        return context

现在在 template.html 中：

{% if prev %}
<a class="nav-link-prev"
   href="{% url "post_detail" pk=prev.id %}">Previous
</a>
{% endif %}

{% if next %}
    <a class="nav-link-next"
       href="{% url "post_detail" pk=next.id %}">Next
    </a>
{% endif %}

您如何看待这种方法？

Answer 3

我认为你必须使用 DetailView 和 mixin MultipleObjectMixin 如下...

from django.views.generic.detail import DetailView
from django.views.generic.list import MultipleObjectMixin
from django.core import paginator

class PostDetailView(DetailView, MultipleObjectMixin):
    model = Post
    paginate_by = 5

    def get_context_data(self, **kwargs):
        object_list = Post.objects.all().order_by('-date_created')
        context = super(PostDetailView, self).get_context_data(object_list=object_list, **kwargs)
        post_paginator = paginator.Paginator(object_list, self.paginate_by)
        # Catch invalid page numbers
        try:
            post_page_obj = post_paginator.page(purchases_page)
        except (paginator.PageNotAnInteger, paginator.EmptyPage):
            post_page_obj = post_paginator.page(1)

        context["post_page_obj"] = post_page_obj
        return context

现在，您应该可以使用带有post_page_obj 变量的分页方法了