Django default values depend on selected value

Question

I am working on a small Transport planner app. I have a Model as follows. I have four widgets to select, but I want to select only the store_name field and with this selection I want to set default values for the other three fields. It would be practical to set the default value for all with only one selection, because most of the cases I use this default value. The default values are in the Store Model. Do you have any idea how can I do it? Thank you in advance!

class StoreNumber(models.Model):
    number = models.CharField(max_length=10, default=None) 

    def __str__(self):
        return str(self.number)


class TransportCompany(models.Model):
    name = models.CharField(max_length=100, default=None) 

    def __str__(self):
        return self.name


class Store(models.Model):
    name = models.CharField(max_length=100, default=None) 
    default_store_number = models.CharField(max_length=100, default=None)
    default_company = models.ForeignKey(TransportCompany, null=True, on_delete=models.SET_NULL)
    default_expedition_time = models.TimeField(default=None)

    def __str__(self):
        return str(self.name)


class Transport(models.Model):
    store_name = models.ForeignKey(Store, null=True, on_delete=models.SET_NULL) 
    store_number = models.ForeignKey(StoreNumber, null=True, on_delete=models.SET_NULL)
    transport_company = models.ForeignKey(TransportCompany, null=True, on_delete=models.SET_NULL)
    expedition_time = models.TimeField(default=None)

    def __str__(self):
        return str(self.expedition_time) + ' | ' + str(self.store_name) + ' | ' + str(self.store_number)
    
    def get_absolute_url(self):
        return reverse('transportplanner')

The form.py:

store_choices = Store.objects.all().values_list('name','name')
store_choice_list = []
for item in store_choices:
    store_choice_list.append(item)

store_number_choices = StoreNumber.objects.all().values_list('number','number')
store_number_choice_list = []
for item in store_number_choices:
    store_number_choice_list.append(item)

company_choices = TransportCompany.objects.all().values_list('name','name')
company_choice_list = []
for item in company_choices:
    company_choice_list.append(item)


class TransportForm(forms.ModelForm):
        class Meta:
            model = Transport
            fields = ('store_name', 'store_number', 'transport_company', 'expedition_time')

            widgets = {
                'store_name': forms.Select(choices=store_choice_list, attrs={'class': 'form-control'}),
                'store_number': forms.Select(choices=store_number_choice_list, attrs={'class': 'form- 
                 control'}),
                'transport_company': forms.Select(choices=company_choice_list, attrs={'class': 'form- 
                 control'}),
                'expedition_time': TimePickerInput(attrs={'class': 'form-control'}, options= 
                 {"enableTime": "true", "noCalendar": "true", "dateFormat": "H:i", "time_24hr": "true", 
                 "defaultDate":"12:00"}),
        }

question from:https://stackoverflow.com/questions/65911383/django-default-values-depend-on-selected-value

Answer 1

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