Setting queryset within forms.ModelChoiceField() - django

Question

The queryset for the 'jurisdiction' field is set below in the initialization. The queryset is dependent on the id that is passed in, which comes from a specific link that a user clicks. As a result, I can't define a singular queryset within the forms.ModelChoiceField(), but it seems that django requires me to do this.
class TaxForm (forms.ModelForm): #Will be used for state tax and other taxes
jurisdiction = forms.ModelChoiceField(queryset=?????)
class Meta:
model = Tax
exclude = ('user', 'taxtype',)
def __init__(self, *args, **kwargs):
self.taxtype = kwargs.pop('taxtype',None)
super(TaxForm, self).__init__(*args, **kwargs)
if int(self.taxtype) == 1:
self.fields['jurisdiction'].choices = [(t.id, t) for t in State.objects.all()]
elif int(self.taxtype) == 2:
self.fields['jurisdiction'].choices = [(t.id, t) for t in Country.objects.all()]
else:
self.fields['jurisdiction'].choices = [(t.id, t) for t in State.objects.none()]
How can I indicate that I want the jurisdiction field to be a dropdown, but not specify one queryset within the forms.ModelChoiceField()? Alternatively, how can I make the queryset that is referenced in forms.ModelChoiceField() refer to the queryset that I initialize based on the taxtype?
Thanks!
Here is my tax model
class Tax(models.Model):
user = models.ForeignKey(User, on_delete=models.CASCADE, default=None)
jurisdiction = models.CharField(max_length=120, null=True, blank=True)
name = models.CharField(max_length=200)
rate = models.DecimalField(max_digits=10, decimal_places=2)
basis = models.CharField(max_length=120, null=True, blank=True)
regnumber = models.CharField(max_length=200, null=True, blank=True) #tax number that will appear on customer invoice
taxtype = models.IntegerField(blank=True, null=True) # 0 is other, 1 is state, 2 is federal
def __str__(self):
return '{} - {}'.format(self.user, self.name)

Answer 1

As I mentioned, ModelChoiceField is not the right thing to do here. That's for allowing the user to choose from related items from a single model that will be saved into a ForeignKey. You don't have a ForeignKey, and what's more you're setting the choices attribute in your init rather than queryset. You should make it a plain ChoiceField with an empty choices parameter:
jurisdiction = forms.ChoiceField(choices=())
(For the sake of completeness: if you did need to use ModelChoiceField you can put anything you like into the queryset parameter when you're overwriting it in __init__, because it will never be evaluated. But managers have a none method which returns an empty queryset, so you could do queryset=State.objects.none().)