Python 字段'；产品标识'；应为一个数字，但得到'&书信电报；django.db.models.query_utils.DeferredAttribute对象位于0x0000022D29594848>'；

您好，正在尝试使用django保存数据并将其显示在我的购物车上。当我尝试将产品添加到购物车时，它会给我一个值错误。错误消息为：字段“Product_id”应为数字，但得到“”。以下是我的购物车文件源代码：

from decimal import Decimal
from django.conf import settings
from store.models import Product

class Cart(object):

    def __init__(self, request):
        """
        Initialize the cart.
        """
        self.session = request.session
        cart = self.session.get(settings.CART_SESSION_ID)
        if not cart:
            # save an empty cart in the session
            cart = self.session[settings.CART_SESSION_ID] = {}
        self.cart = cart

    def __iter__(self):
        """
        Iterate over the items in the cart and get the products
        from the database.
        """
        product_ids = self.cart.keys()
        # get the product objects and add them to the cart
        products = Product.objects.filter(Product_id__in=product_ids)

        cart = self.cart.copy()
        for product in products:
            cart[str(product.Product_id)]['product'] = product

        for item in cart.values():
            item['Price'] = Decimal(item['Price'])
            item['total_price'] = item['Price'] * item['Quantity']
            yield item

    def __len__(self):
        """
        Count all items in the cart.
        """
        return sum(item['Quantity'] for item in self.cart.values())

    def add(self, product, quantity=1, override_quantity=False):
        """
        Add a product to the cart or update its quantity.
        """
        product_id = str(product.Product_id)
        if product_id not in self.cart:
            self.cart[product_id] = {'quantity': 0,
                                      'price': str(product.Price)}
        if override_quantity:
            self.cart[product_id]['quantity'] = quantity
        else:
            self.cart[product_id]['quantity'] += quantity
        self.save()

    def save(self):
        # mark the session as "modified" to make sure it gets saved
        self.session.modified = True

    def remove(self, product):
        """
        Remove a product from the cart.
        """
        product_id = str(product.Product_id)
        if product_id in self.cart:
            del self.cart[product_id]
            self.save()

    def clear(self):
        # remove cart from session
        del self.session[settings.CART_SESSION_ID]
        self.save()

    def get_total_price(self):
        return sum(Decimal(item['price']) * item['quantity'] for item in self.cart.values())

我的模型：

from django.db import models
from django.urls import reverse
# Create your models here.
class Customer(models.Model):
    Phone_number = models.IntegerField(primary_key=True)
    First_name = models.CharField(max_length=50)
    Last_name = models.CharField(max_length=50)
    date_and_time_created = models.DateTimeField(auto_now=True)

class Category(models.Model):
    Category_name = models.CharField(max_length=248, primary_key=True)

class Product(models.Model):
    Product_id = models.IntegerField(primary_key=True)
    Product_name = models.CharField(max_length=100)
    Product_image = models.ImageField(null=True,blank=True)
    Price = models.IntegerField()
    discount_price = models.IntegerField(null=True)
    Quantity = models.IntegerField()
    description = models.TextField(null=True)
    category = models.OneToOneField(Category, null=True, on_delete=models.CASCADE)

   
    def get_absolute_url(self):
        return reverse('store:prod',kwargs={'pk':self.Product_id})

class Order(models.Model):
    order_id = models.IntegerField(primary_key=True)
    billing_address = models.CharField(max_length=248)
    Shipping_address = models.CharField(max_length=248)
    date_and_time_ordered = models.DateTimeField(auto_now=True)
    #add time of delivery
    customer = models.ForeignKey(Customer, null=True, on_delete=models.SET_NULL)
    product =models.ForeignKey(Product, null=True, on_delete=models.SET_NULL)

my views for the cart:
from django.shortcuts import render, redirect, get_object_or_404
from django.views.decorators.http import require_POST
from store.models import Product
from .cart import Cart
from .forms import CartAddProductForm

@require_POST
def cart_add(request, product_id):
    cart = Cart(request)
    product = get_object_or_404(Product, Product_id=product_id)
    form = CartAddProductForm(request.POST)
    if form.is_valid():
        cd = form.cleaned_data
        cart.add(product=product,
                 quantity=cd['quantity'],
                 override_quantity=cd['override'])
    return redirect('cartapp:cart_detail')


@require_POST
def cart_remove(request, product_id):
    cart = Cart(request)
    product = get_object_or_404(Product, Product_id=product_id)
    cart.remove(product)
    return redirect('cartapp:cart_detail')


def cart_detail(request):
    cart = Cart(request)
    for item in cart:
        item['update_quantity_form'] = CartAddProductForm(initial={'quantity': item['quantity'],
                                                                   'override': True})
    return render(request, 'cartapp/detail.html', {'cart': cart})

我的购物车URL.py：

    from django.urls import path, re_path
from cartapp import views
app_name = 'cartapp'

urlpatterns = [
    path('', views.cart_detail, name='cart_detail'),
    path('add/<product_id>/', views.cart_add, name='cart_add'),
    path('remove/<int:product_id>/', views.cart_remove, name='cart_remove'),


]

---

希望我发布了正确的信息。我将感谢所有能得到的帮助。

我清除了我的会话和cookie数据，它成功了。

在卡添加（..，产品id）和卡删除（..产品id）中，您分配产品id=产品id。。。如何调用函数或为product\u id参数分配什么？共享您的

CartAddProductForm

@Razenstein。product\u id是模型中原始product\u id的字符串格式。它在cart.py文件夹中，我在cart@NKSM刚刚更新过

from django import forms


PRODUCT_QUANTITY_CHOICES = [(i, str(i)) for i in range(1, 21)]


    class CartAddProductForm(forms.Form):
        quantity = forms.TypedChoiceField(
                                    choices=PRODUCT_QUANTITY_CHOICES,
                                    coerce=int)
        override = forms.BooleanField(required=False,
                                      initial=False,
                                      widget=forms.HiddenInput)