ValueError at /newspaperapp/category/sports/ : Field 'id‘应为数字，但获取的是'sports’

Question

我正在为新闻创建分类。我正在尝试过滤新闻类别，但得到一个值错误models.py

class category(models.Model):
    title = models.CharField(max_length=199)
    category_image = models.ImageField(upload_to="imgs")

    def __str__(self):
        return self.title


class newsmodel_0(models.Model):
    category = models.ForeignKey(category, on_delete=models.CASCADE)
    title = models.CharField(max_length=49, null=False, blank=False)
    date_published = models.DateTimeField(auto_now_add=True)
    # details = models.TextField()
    details = RichTextUploadingField(blank=True, null=True)
    slug = models.SlugField(blank=True, unique=True)

    def slug(self):
        return slugify(self.date_published)

这是views.py

  def index(request):
    cats = category.objects.all()
    return render(request, 'newspaperapp/index.html', {'cats': cats})


class nowlist(ListView):
    model = newsmodel_1
    template_name = 'newspaperapp/index.html'


class newslist(DetailView):
    model = newsmodel_1
    template_name = 'newspaperapp/home.html'
    context_object_name = 'newspaperapp'


class SearchView(ListView):
    model = newsmodel_1
    template_name = 'newspaperapp/search.html'
    context_object_name = 'all_search_results'

    def get_queryset(self):
        result = super(SearchView, self).get_queryset()
        query = self.request.GET.get('search')
        # query is of type 'str', convert to datetime
        start_day = datetime.fromisoformat(query)
        end_day = start_day + timedelta(days=1)
        if query:
            postresult = newsmodel_1.objects.filter(
                date_published__gte=start_day,
                date_published__lt=end_day
            )
            result = postresult
        else:
            result = None
        return result


def full_news(request):
    return render(request, 'newspaperapp/full-news.html')


def CategoryView(request, cats):
    category_posts = newsmodel_1.objects.filter(category=cats)
    return render(request, "newspaperapp/categories.html", {'cats': cats, 'category_posts': category_posts})

这是urls.py

urlpatterns = [
  path('',views.index,name='index'),
  path('date/',nowlist.as_view(),name = "date"),
  path('<int:pk>',newslist.as_view(),name = "home"),
  path('results/', SearchView.as_view(), name='search'),
  path('full_news/',views.full_news,name = "full_news"),
  path('category/<str:cats>/',views.CategoryView,name='category'),
  ]

categories.html

<h1>{{cats}} category</h1>
<ul>
 {%for post in category_posts%}
   <h3><a href="{%url 'newspaperapp:index'  %}">{{ newspaperapp.title}} 
    {{newspaperapp.category}}</a></h3>
 {% endfor %}

index.html

{% for cat in cats %}
    <p class="card-text"><a href="category/{{cat.id}}" class="btn btn-sm btn-primary">{{cat.title}} 
     </a></p>
{% endfor %}

如果我使用#category_posts = newsmodel_1.objects.filter(category__name = cats)，那么我会在/newspaperapp/category/sports/ Related Field got lookup: FieldError中得到一个错误

我已经更改了catogories.html中的代码，但它并没有显示体育新闻，而只是打印“体育类别”。

Answer 1

在您的CategoryView中，而不是使用以下内容：

def CategoryView(request, cats):
    category_posts = newsmodel_1.objects.filter(category=cats)
    return render(request, "newspaperapp/categories.html", {'cats': cats, 'category_posts': category_posts})

试试这个：

def CategoryView(request, cats):
    cats = Category.objects.get(title=cats) # this will give the Category instance instead of string cats
    category_posts = newsmodel_1.objects.filter(category=cats)
    return render(request, "newspaperapp/categories.html", {'cats': cats, 'category_posts': category_posts})

我希望这对你有用。