Django items = order.orderitem_set.all() 返回数量的空值

Question

当我尝试将{{ item.product.quantity }}放入其中时，返回一个空值。数量值将填充到数据库中。我似乎无法确定问题所在。我尝试打印数量值，但得到了相同的结果。

购物车.html

{% extends 'store/main.html' %}
{% load static %}
{% block content %}
<div class="row">
<div class="col-lg-12">
<div class="box-element">
<a  class="btn btn-outline-dark" href="{% url 'store' %}">&#x2190; Continue Shopping</a>
<br>
<br>
<table class="table">
<tr>
<th><h5>Items: <strong>3</strong></h5></th>
<th><h5>Total:<strong> $42</strong></h5></th>
<th>
<a  style="float:right; margin:5px;" class="btn btn-success" href="{% url 'checkout' %}">Checkout</a>
</th>
</tr>
</table>
</div>
<br>
<div class="box-element">
<div class="cart-row">
<div style="flex:2"></div>
<div style="flex:2"><strong>Item</strong></div>
<div style="flex:1"><strong>Price</strong></div>
<div style="flex:1"><strong>Quantity</strong></div>
<div style="flex:1"><strong>Total</strong></div>
</div>
{% for item in items %}
<div class="cart-row">
<div style="flex:2"><img class="row-image" src="{{ item.product.imageURL }}"></div>
<div style="flex:2"><p>{{ item.product.name }}</p></div>
<div style="flex:1"><p>R{{ item.product.price|floatformat:2 }}</p></div>
<div style="flex:1">
<p class="quantity">{{ item.product.quantity }}</p>
<div class="quantity">
<img class="chg-quantity" src="{% static  'images/arrow-up.png' %}">
<img class="chg-quantity" src="{% static  'images/arrow-down.png' %}">
</div>
</div>
<div style="flex:1"><p>$32</p></div>
</div>
{% endfor %}
</div>
</div>
</div>
{% endblock content %}

views.py

from django.shortcuts import render
from .models import *
def store(request):
search = request.GET.get('search')
products = Product.objects.all()
if search != '' and search is not None:
products = products.filter(name__icontains=search)
context= {'products': products}
return render(request, 'store/store.html', context)

def cart(request):
if request.user.is_authenticated:
customer = request.user.customer
order, created = Order.objects.get_or_create(customer=customer, complete=False)
items = order.orderitem_set.all()
else:
items = []
context= {'items': items}
return render(request, 'store/cart.html', context)
def checkout(request):
context= {}
return render(request, 'store/checkout.html', context)

models.py

from django.db import models
from django.contrib.auth.models import User

class Customer(models.Model):
user = models.OneToOneField(User, null=True, blank=True, on_delete=models.CASCADE)
name = models.CharField(max_length=200, null=True)
email = models.CharField(max_length=200)
def __str__(self):
return self.name

class Product(models.Model):
name = models.CharField(max_length=200, null=True)
price = models.FloatField()
digital = models.BooleanField(default=False, null=True, blank=True)
image = models.ImageField(null=True, blank=True)
def __str__(self):
return self.name
@property
def imageURL(self):
try:
url = self.image.url
except:
url = ''
return url

class Order(models.Model):
customer = models.ForeignKey(Customer, on_delete=models.SET_NULL, null=True, blank=True)
date_ordered = models.DateTimeField(auto_now_add=True)
complete = models.BooleanField(default=False, null=True, blank=False)
transaction_id = models.CharField(max_length=100, null=True)
def __str__(self):
return str(self.id)
class OrderItem(models.Model):
product = models.ForeignKey(Product, on_delete=models.SET_NULL, null=True)
order = models.ForeignKey(Order, on_delete=models.SET_NULL, null=True)
quantity = models.IntegerField(default=0, null=True, blank=True)
date_added = models.DateTimeField(auto_now_add=True)

class ShippingAddress(models.Model):
customer = models.ForeignKey(Customer, on_delete=models.SET_NULL, null=True)
order = models.ForeignKey(Order, on_delete=models.SET_NULL, null=True)
address = models.CharField(max_length=200, null=False)
city = models.CharField(max_length=200, null=False)
state = models.CharField(max_length=200, null=False)
zipcode = models.CharField(max_length=200, null=False)
date_added = models.DateTimeField(auto_now_add=True)
def __str__(self):
return self.address

如果我这样做print(items)结果将是：

<QuerySet [<OrderItem: OrderItem object (4)>, <OrderItem: OrderItem object (5)>]>

Answer 1

所以quantity是模型OrderItem的一个字段。

对返回的items对象的查询为：

order, created = Order.objects.get_or_create(customer=customer, complete=False)

Order是：

class Order(models.Model):
customer = models.ForeignKey(Customer, on_delete=models.SET_NULL, null=True, blank=True)
date_ordered = models.DateTimeField(auto_now_add=True)
complete = models.BooleanField(default=False, null=True, blank=False)
transaction_id = models.CharField(max_length=100, null=True)
def __str__(self):
return str(self.id)

和quantity

class OrderItem(models.Model):
product = models.ForeignKey(Product, on_delete=models.SET_NULL, null=True)
order = models.ForeignKey(Order, on_delete=models.SET_NULL, null=True)
quantity = models.IntegerField(default=0, null=True, blank=True)
date_added = models.DateTimeField(auto_now_add=True)

所以你返回的对象不包含

{{ item.product.quantity }}

所以你必须使用(感谢您@Jakumi突出显示它(

{{ item.quantity }}