如何解决无法在HTML模板中使用模型属性
我正在为电子产品制作电子商务应用程序,并且为每个类别分别制作了模型。 因此,在购物车页面上,我无法求和商品的总价值。
我收到此错误
/ cart /中的 AttributeError
'NoneType'对象没有属性'price'
请求方法:GET
要求网址:http://127.0.0.1:8000/cart/
Django版本:3.0.7
异常类型:AttributeError
异常值:
'NoneType'对象没有属性'price'
异常位置:get_laptop_total,第123行中的D:\ WebDev \ my_projects \ techcastle \ store \ models.py
Python可执行文件:D:\ WebDev \ my_projects \ env \ Scripts \ python.exe
Python版本:3.8.0
我的模特:-
class Mobile(models.Model):
name = models.CharField(max_length=200)
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 Laptop(models.Model):
name = models.CharField(max_length=200)
price = models.FloatField()
digital = models.BooleanField(default=False,blank=True)
def __str__(self):
return self.name
@property
def imageURL(self):
try:
url = self.image.url
except:
url = ''
return url
class Accessories(models.Model):
name = models.CharField(max_length=200)
price = models.FloatField()
digital = models.BooleanField(default=False,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,blank=True,null=True)
date_ordered = models.DateTimeField(auto_now_add=True)
completed = models.BooleanField(default=False,blank=False)
transaction_id = models.CharField(max_length=200)
def __str__(self):
return str(self.id)
@property
def get_cart_total(self):
orderitems = self.orderitem_set.all()
total = sum([item.get_laptop_total for item in orderitems] + sum([item.get_mobile_total for item in orderitems])
+ sum([item.get_acc_total for item in orderitems] ))
return total
@property
def get_cart_item(self):
orderitems = self.orderitem_set.all()
total = sum([item.quantity for item in orderitems])
return total
class OrderItem(models.Model):
product_m = models.ForeignKey(Mobile,blank=True)
product_l = models.ForeignKey(Laptop,blank=True)
product_a = models.ForeignKey(Accessories,blank=True)
order = models.ForeignKey(Order,blank=True)
quantity = models.IntegerField(default=0,blank=True)
date_added = models.DateTimeField(auto_now_add=True)
def __str__(self):
if (self.product_l is not None):
return (self.product_l.name)
elif (self.product_a is not None):
return (self.product_a.name)
elif (self.product_m is not None):
return (self.product_m.name)
@property
def get_mobile_total(self):
total_m = self.product_m.price * self.quantity
return total_m
@property
def get_acc_total(self):
total_a = self.product_a.price * self.quantity
return total_a
@property
def get_laptop_total(self):
total_l = self.product_l.price * self.quantity
return total_l
我的观点
def cart(request):
if request.user.is_authenticated:
customer = request.user.customer
order,created = Order.objects.get_or_create(customer=customer,completed=False)
items=order.orderitem_set.all()
context = {'items':items,'order':order }
return render(request,'store/cart.html',context)
模板
<div class="row">
<div class="col-lg-12">
<div class="box-element">
<a class="btn btn-outline-dark" href="{% url 'store' %}">← Continue Shopping</a>
<br>
<br>
<table class="table">
<tr>
<th><h5>Items : <strong> {{order.get_cart_item}}</strong></h5></th>
**<th><h5>Total : <strong> {{order.get_cart_total}} </strong></h5></th>
<th>**
<a style="float:right; margin:5px;" class="btn btn-success" href="{% url 'checkout' %}">Checkout</a>
</th>
</tr>
</table>
</div>
解决方法
我的理论:在Order.get_cart_total()中,您可以在购物车中的每个项目上调用笔记本电脑的sum函数,而无需检查是否将其分配给具有外键的笔记本电脑。移动版和广告版相同。因此,在您的OrderItem方法中,您需要首先检查是否是笔记本电脑。试试:
def get_laptop_total(self):
if self.product_l:
total_l = self.product_l.price * self.quantity
return total_l
else:
return 0
,
django是区分大小写的语言。您应该检查在def get_cart_item(self)
和def get_cart_total(self)
中提到的类名的拼写。
应该是:-
@property
def get_cart_total(self):
orderitems = self.Orderitem_set.all()
total = sum([item.get_laptop_total for item in orderitems] + sum([item.get_mobile_total for item in orderitems])
+ sum([item.get_acc_total for item in orderitems] ))
return total
@property
def get_cart_item(self):
orderitems = self.Orderitem_set.all()
total = sum([item.quantity for item in orderitems])
return total
,
请尝试使用get_laptop_total
,而不是self.product_l__price * self.quantity
中的&
。我希望这行得通。
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