AttributeError：“NoneType”对象没有属性“_meta”Django

Question

我是新手 我想更改选定的数据（food_status）并将其保存到选定的列（food_status 列）。但它显示错误

对于 self._meta.concrete_fields 中的字段： AttributeError：“NoneType”对象没有属性“_meta”

在这部分

OrderItem.save(food_status, update_fields=['food_status'])

模型.py

class OrderItem(models.Model):
    Table_No = models.IntegerField(blank=False)
    FoodId = models.TextField()
    Item = models.TextField()
    Qty = models.IntegerField(blank=False)
    Price = models.TextField()
    Note = models.TextField(max_length=100, null=True)
    OrderId = models.TextField(max_length=100, null=True)

    FoodStatus = (
       ('1', 'Has been ordered'),
       ('2', 'cooked'),
       ('3', 'ready to be served'),
       ('4', 'done'),
     )
   food_status = models.CharField(max_length=50, choices=FoodStatus, 
         default="has been ordered")

views.py

def kitchen_view(request):
    chef_view = OrderItem.objects.all()
    if request.method == "POST":
       food_status = request.POST.get("food_status")
       OrderItem.food_status = food_status
       OrderItem.save(food_status, update_fields=['food_status'])
    return render(request, 'restaurants/kitchen_page.html', {'chef_view':chef_view})

kitchen_page.html

 <form action="#" method="post">
 {% csrf_token %}
 {% for order in chef_view %}
    <table width="800">
    <tr>
    <th width="800">Table Number</th>
    <th width="800">Item</th>
    <th width="800">Quantity</th>
    <th width="800">Price</th>
    <th width="800">Note</th>
    <th width="800">Order Id</th>
    <th width="800">Status</th>
   </tr>
   <tr>
    <td width="800">{{ order.Table_No }}</td>
    <td width="800">{{ order.Item }}</td>
    <td width="800">{{ order.Qty }}</td>
    <td width="800">{{ order.Price }}</td>
    <td width="800">{{ order.Note }}</td>
    <td width="800">{{ order.OrderId }}</td>
    <td width="800">{{ order.Status }} 
        <button type="button" class="close" data-dismiss="modal" aria- 
            label="Close"><span class="glyphicon glyphicon-pencil"  aria- 
            hidden="true">&times;</span></button>
    <select>
        <option name="food_status" id="1" value="None">Has been 
                ordered</option>
        <option name="food_status" id="2" 
                value="Cooked">Cooked</option>
        <option name="food_status" id="3" value="Ready to be 
                served">Ready to be served</option>
        <option name="food_status" id="4" 
                value="Done">Done</option>
        </select>
        <a href='' button onclick="myFunction()"><input 
                type="submit" value="Change Status"></button>
    </td>
       </tr>
</table>
  {% endfor %}
  </form>

代码应根据 html 中的选择选项将 food_status 保存到 food_status 数据库列。

有人可以帮助我吗？真的很欣赏

Answer 1

您已经差不多明白了，但只是顺序不太正确。在创建

OrderItem.food_status = ...

实例之前，您不能执行

OrderItem

操作。例如，这可以工作：

order_item = OrderItem()
order_item.food_status = food_status
order_item.save()

尝试使用以下内容，更完整：

def kitchen_view(request):
    chef_view = OrderItem.objects.all()
    if request.method == "POST":
       food_status = request.POST.get("food_status")
       order_item = OrderItem(food_status=food_status)
       order_item.save()

    return render(request, 'restaurants/kitchen_page.html', {'chef_view':chef_view})