无法在HTML模板中使用模型属性

编程问答 2022-12-06

问题描述

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' %}">&#x2190; 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。

djangohtmlmodelmodelpythonviewview