Django：Select 是一个有效的选择。 该选择不是可用的选择之一

Question

I have a nested choice field: The top one is used to select a smartphone brand and the bottom one is used to select a smartphone model of the said brand.

The problem I face is such that when restricting the bottom choice using AJAX, my form is invalid. However, the POST request with and without restriction are exactly the same:

No restriction:

{'name': 'Ok iPhone 12 Mini', 'price': Decimal('345'), 'color': <Color: Red>, 'condition': <Condition: Refurbished by manufacturer>, 'storage': <StorageChoice: 128>, 'phone_model': <PhoneModel: iPhone 12 Mini>, 'description': '...', 'image': <InMemoryUploadedFile: pic.jpg (image/jpeg)>}

With restriction:

{'name': 'Ok iPhone 12 Mini', 'price': Decimal('345'), 'color': <Color: Red>, 'condition': <Condition: Refurbished by manufacturer>, 'storage': <StorageChoice: 128>, 'description': '...', 'image': <InMemoryUploadedFile: pic.jpg (image/jpeg)>, 'phone_model': <PhoneModel: iPhone 12 Mini>}

The only difference I can see is order, which should not matter in the case of a dictionary.

views.py:

def product_add(request):
    form = AddProductForm()
    if request.method == "POST":
        form = AddProductForm(request.POST, request.FILES)
        form.is_valid()
        form.cleaned_data['phone_model'] = PhoneModel.objects.get(id=request.POST['phone_model'])
        form.cleaned_data.pop('make', None)
        print(form.cleaned_data)
        if form.is_valid():
            form.cleaned_data['seller'] = request.user.customer
            Product.objects.create(**form.cleaned_data)
        else:
            print(form.errors)
    cart = get_cart(request)
    context = {'form': form, **cart}
    return render(request, 'store/product_add.html', context)

def load_models(request):
    make_id = request.GET.get('make')
    models = PhoneModel.objects.filter(phone_make=make_id)
    return render(request, 'part/product_add_model_options.html', {'models': models})

forms.py:

class AddProductForm(forms.ModelForm):
    class Meta:
        model = Product
        fields = ['name', 'price', 'color', 'condition',
                  'storage', 'phone_model', 'description', 'image']

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        make = forms.ModelChoiceField(
            queryset=PhoneMake.objects.all(), required=False)
        self.fields['make'] = make
        self.fields['phone_model'].queryset = PhoneModel.objects.none()
        if 'make' in self.data:
            try:
                make_id = int(self.data.get('make'))
                self.fields['phone_model'].queryset = PhoneModel.objects.filter(
                    phone_make__phone_make=make_id)
            except Exception as e:
                print(e)

product.html (used with Jquery script to insert "options" into this "select"):

  <select name="phone_model" required id="id_model"> </select>

product_option.html:

<option value="">---------</option>
{% for model in models %}
<option value="{{ model.id }}">{{ model }}</option>
{% endfor %}

Answer 1

init method in the AddProductForm has following query self.fields['phone_model'].queryset = PhoneModel.objects.filter(phone_make__phone_make=make_id) it should be

self.fields['phone_model'].queryset = PhoneModel.objects.filter(
                phone_make=make_id)

, "phone_make" field is mentioned twice in your filter