Question

为简单起见，这是我正在处理的问题的简短版本。假设您有两个模型，分别是Product和ProductPricing，其中Product具有许多ProductPricing实例，并且一个产品的定价仅与一个产品有关（一对多关系）。模型的清洁方法：

models.py：

class ProductPricing(models.Model):
    product = models.ForeignKey(Product, related_name = 'prices', verbose_name = 'Price', blank = True, null = True)
    customer = models.ForeignKey(Customer, related_name = 'customer_pricings', blank = True, null = True)
    ...
    def clean(self):
        if not self.product and not self.customer:
            raise ValidationError(_('Pricing requires either a product or a customer. None is provided') )

forms.py：

class ProductPricingAddonForm(ModelForm):    
    class Meta:
        model = ProductPricing
        fields = ['UOM', 'cost_per_UOM', 'product']

现在，在我的UpdateView中，我正在执行以下操作：

class UpdateProductView(View):
    template_name = 'product.html'
    product_form = ProductForm
    pricing_form = ProductPricingAddonForm

    def get(self, request, *args, **kwargs):
        product_id = kwargs.get('pk', None)
        product = Product.objects.get(id = product_id)

        product_form = self.product_form()
        pricing_form = self.pricing_form()

        c = {}
        c['product_form'] = product_form
        c['pricing_form'] = pricing_form

        return render(request, self.template_name, c)

    def post(self, request, *args, **kwargs):
        ''' To update both the models in one go'''

        product_id = kwargs.get('pk', None)
        product = Product.objects.get(id = product_id)
        product_pricing = ProductPricing.objects.filter(product = product)

        product_form = self.product_form(request.POST if any(request.POST) else None, request.FILES or None, instance = product)
        if product_form.is_valid():
            product_form.save()
            product_form_validity_flag = True
            updated_product = Product.objects.get(id = product_id)
        else:
            product_form_errors = product_form.errors
        ...
        # if no existing pricing specified for the product:
        pricing_form = self.pricing_form(request.POST if any(request.POST) else None, request.FILES or None)    
        # Since a productpricing instance is required to have product or customer, the updated_product should somehow be attached to the form:
        pricing_form['product'] = updated_product     # <-- Error here
        if pricing_form.is_valid():
            pricing_form.save()
            pricing_form_validity_flag
        else:
            pricing_form_errors = pricing_form.errors

        if product_form_validity_flag and pricing_form_validity_flag:
            return reverse(...)
        else:
            c = {'product_form': product_form,
                  'pricing_form': pricing_form }
            return render(request, self.template_name, c)

问题是提交表单时，出现错误消息“ ProductPricingAddonForm”对象不支持项目分配。请注意，如果我不以某种方式将产品提供给productpricing表单，则ProductPricing模型的clean方法中定义的验证错误将引发我。

所以，我的问题是如何在相同的post方法中将父实例（产品）附加到子实例（产品定价）（即不在其他页面中创建产品定价）？

Django如何在一篇文章中处理模型之间一对多关系的两种形式

0 个答案: