动态更改Django的views.py文件中的表单字段

Question

I was wondering if there is a way that I can alter a model form within the views.py file to create a multiple choice dropdown field for form choices. I want to set each option on the choice field from the results of a queryset.

for example: I want to from_acct field to have a scroll down option with the following list.. wells fargo chase tabz bank of america

the list of banks are results of a query set

Here is what i have so far in the views.py file.

form = TransferForm()
        form.fields['from_acct'].queryset = Accounts.objects.filter(user = currentUser).all()
        message = 'please fill out the below form'
        parameters = {
            'form':form,
            'currentUser':currentUser,
            'message':message,
        }
        return render(request, 'tabs/user_balance.html', parameters)

here is the forms.py file

class TransferForm(forms.ModelForm):
    class Meta:
        model = Transfers
        fields = ['from_acct', 'to_acct', 'amount', 'memo']
        labels = {
            'from_acct':'from',
            'to_acct':'to',
        }

here is the model.py file

class Transfers(models.Model):
    user = models.ForeignKey(User, on_delete=models.CASCADE)
    from_acct = models.CharField(max_length=150, default='account')
    to_acct = models.CharField(max_length=150, default='accont')
    amount = models.DecimalField(decimal_places=2, max_digits=9, default=0)
    memo = models.CharField(max_length=200, default='memo')
    frequency = models.SmallIntegerField(default=1)
    status = models.SmallIntegerField(default=1)
    create = models.DateTimeField(auto_now_add=True)

Answer 1

You can try to set choices arg for CharField by function.

Like that:

class Transfers(models.Model):
    field = models.CharField(max_length=255, choices=result_query())
    def result_query(self):
        # you can use that with self if u need transfers.pk for querying
        return Something.objects.exclude(bank_id__in=[bank.id for bank in self.banks.all())

def result_query():
    # or there if not
    return Something.objects.filter(any_field__gte=123)

For sure, you can realize any logic in the function, so you can dynamically change options for char field.

UPDATE:

Sure, u haven't pass request into the function. That should be like that:

view.py:

def my_view(request):
    if request.method == 'GET':
        form = TransferForm(user=request.user)
    ...
    return something here

forms.py

class TransferForm(ModelForm):
    class Meta:
        model = Transfer

    def __init__(self, *args, **kwargs):
        user = kwargs.pop('user')
        super(TransferForm, self).__init__(*args, **kwargs)
        self.fields['accounts'].choices = Accounts.objects.filter(user = currentUser).all()