代码之家 › 专栏 › 技术社区 › Nikita Tonkoskur

“ReverseManyToOneDescriptor”对象没有“all”属性

django python

Nikita Tonkoskur · 技术社区 · 8 年前

我是Django的新手,我正试图通过 Category 模型。我在用外键 Product 对于类别。这些是我的模型:

class Category(models.Model):
    name = models.CharField(max_length=140)
    slug = models.SlugField(blank=True)

    def __str__(self):
        return self.name

    def get_absolute_url(self):
        return reverse("shop:category", kwargs= 
                {"category_slug": self.slug})

class Product(models.Model):
    category = models.ForeignKey(Category, 
                               on_delete=models.CASCADE)
    brand = models.ForeignKey(Brand, 
                               on_delete=models.CASCADE)
    title = models.CharField(max_length=200)
    slug = models.SlugField()
    description = models.TextField()
    image = models.ImageField(upload_to=image_name)
    price = models.PositiveIntegerField()
    avaliable = models.BooleanField(default=True)

    def get_absolute_url(self):
         return reverse("shop:product", kwargs={
                       "product_slug": self.slug,                                           
                       "product_ctgr_slug": 
                                   self.category.slug,})

我的观点:

class CategoryDetailView(DetailView):
    model = Category
    category_products = Category.product_set.all()
    slug_url_kwarg = "category_slug"

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['categories'] = self.categories
        context['category_products'] = self.category_products
        return context

AttributeError: 'ReverseManyToOneDescriptor' object has no attribute 'all' .

2 回复 | 直到 8 年前

cezar Dennis Kioko 8 年前

你可以用 product_set 作为在Django中默认创建的相关名称,或者您最好自己创建一个相关名称。一个属于类别 ,但是类别可以有很多产品

为此,请为 category Product :

category = models.ForeignKey(
    Category,
    on_delete=models.CASCADE,
    related_name='products'
)

现在在你的 views.py

class CategoryDetailView(DetailView):
    model = Category
    # remove the line below
    category_products = Category.product_set.all()
    # don't prefix the fields like this, it's ugly and redundant
    # call it just slug, not category_slug, adjust in urls.py
    slug_url_kwarg = "category_slug"

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        # where did you get self.categories?
        context['categories'] = self.categories
        # and this won't work anymore too
        context['category_products'] = self.category_products
        return context

在 CategoryDetailView 只显示一个类别。这是一个详细的视图-它只包含一个对象。所以你不会用 . 对象在方法中可用。我们就是这样重写的:

def get_context_data(self, **kwargs):
    context = super().get_context_data(**kwargs)
    products = self.object.products.all()
    context['products'] = products
    return context

Christo 8 年前

def get_context_data(self, **kwargs):
    context = super().get_context_data(**kwargs)
    instance = self.get_object()
    context['categories'] = self.categories
    context['category_products'] = instance.product_set.all()
    return context