如何更新通过外键连接的模型中的字段

Question

我正在处理更新视图，我想通过单击订单视图列表上的项目来更新 T 恤的尺寸。我堆叠在只能显示项目名称但不能更新 T 恤尺寸的位置。这是 Django 3.

请提示，我如何更新通过外键与 Order 模型连接的 T 恤的尺寸。

models.py

class Size(models.TextChoices):
    SMALL = 'S', 'Small'
    MEDIUM = 'M', 'Medium'
    LARGE = 'L', 'Large'


class Tshirt(models.Model):
    name = models.CharField(max_length=255)
    size = models.CharField(max_length=2, choices=Size.choices, default=Size.MEDIUM)

    def __str__(self):
        return self.name

class Order(models.Model):
    nr = models.PositiveIntegerField(unique=True)
    item = models.ForeignKey(Tshirt, related_name='order_tshirts', on_delete=models.CASCADE)
    send_date = models.DateTimeField(null=True, blank=True)
    
    def get_update_size_url(self):
        return reverse('size_update', kwargs={'pk': self.pk})

urls.py

path('update/<int:pk>/', TshirtSizeUpdateView.as_view(), name='size_update'),

views.py

class TshirtSizeUpdateView(UpdateView):
    model = Order
    template_name = 'size_update.html'
    fields = ['item']
    success_url = '/'

forms.py

class OrderForm(forms.ModelForm):
    class Meta:
        model = Order
        fields = '__all__'
```


update template
```
    <form method="post">
        {% csrf_token %}
        {% include 'includes/bs4_form.html' with form=form %}
        <input type="submit" class="btn btn-primary mb-2" value="Update">
    </form>
```

Answer 1

在这种情况下，您可以使用 formset。

在forms.py

from django.forms.models import inlineformset_factory

TshirtFormset = inlineformset_factory(
    Order, Tshirt, fields=('name', 'size')
)

在views.py

class OrderUpdateView(UpdateView):
    model = Order
    fields = ["nr", "item", "send_date"]

    template_name = 'size_update.html'
    success_url = '/'

    def get_context_data(self, **kwargs):
        
        context = super(OrderUpdateView, self).get_context_data(**kwargs)
        if self.request.POST:
            context["tshirt_form"] = TshirtFormset(self.request.POST, instance=self.object)
        else:
            context["tshirt_form"] = TshirtFormset(instance=self.object)

        return context

    def form_valid(self, form):
        context = self.get_context_data()
        tshirt_form = context["tshirt_form"]
        self.object = form.save()
        if tshirt_form.is_valid():
            tshirt_form.instance = self.object
            tshirt_form.save()
        return super(OrderUpdateView, self).form_valid(form)

在您的模板中，放入您的订单和您的 T 恤表单集。

<form method="post">{% csrf_token %}
    {{ form.as_p }}
    <h2>T-shirt detail</h2>
    {{ tshirt_form.as_p }}
    <input type="submit" value="Save">
</form>

如何更新通过外键连接的模型中的字段

How to update field in model connected via foreign key

python

forms

django

view

django-class-based-views