[Fixed]-Django forms give: Select a valid choice. That choice is not one of the available choices

You’re getting a flat value_list back which will just be a list of the ids, but when you do that, you’re probably better off using a plain ChoiceField instead of a ModelChoiceField and providing it with a list of tuples, not just ids. For example:

class CommandSubmitForm(ModelForm):
    iquery = LiveDataFeed.objects.values_list('unit_id', flat=True).distinct()
    iquery_choices = [('', 'None')] + [(id, id) for id in iquery]
    unit_id = forms.ChoiceField(iquery_choices,
                                required=False, widget=forms.Select())

You could also leave it as a ModelChoiceField, and use LiveDataFeed.objects.all() as the queryset, but in order to display the id in the box as well as have it populate for the option values, you’d have to subclass ModelChoiceField to override the label_from_instance method. You can see an example in the docs here.

Before you call form.is_valid(), do the following:

1. unit_id = request.POST.get('unit_id')

2. form.fields['unit_id'].choices = [(unit_id, unit_id)]

Now you can call form.is_valid() and your form will validate correctly.

this is an old question but i faced the same problem, the solution according the django docs is to add to_field_name="name" where name is the column you want to show on the choices

iquery = LiveDataFeed.objects.values_list('unit_id', flat=True).distinct()
unit_id = forms.ModelChoiceField(queryset=iquery, empty_label='None',
    required=False, widget=forms.Select(),to_field_name="unit_id")

Rewrite the _init function. Use Limited_condition variable that delete this field in update view. in my case ‘author’ field caused problem ‘Select a valid choice’. I just removed it in initiation of the form.

forms.py
    class UrlentryForm(ModelForm):
class Meta:
    model = Urlentry
    fields = ['url_text', 'author', 'url_id', 'datetime_available_from', 'datetime_available_to', 'partner_ads','qr_code','snapshot']
def __init__(self, *args, **kwargs):
    limited_condition = kwargs.pop('limited_condition', None)
    super(UrlentryForm, self).__init__(*args, **kwargs)
    if limited_condition:
        del self.fields['author']
        self.fields['url_id'].widget = HiddenInput()
        self.fields['url_id'].required = False
        self.fields['qr_code'].widget = HiddenInput()
        self.fields['qr_code'].required = False
        self.fields['snapshot'].widget = HiddenInput()
        self.fields['snapshot'].required = False

Then modify views.py

views.py
    @login_required(login_url=reverse_lazy('auth:login'))
    def update_urlentry(request, pk):
        #....
    if request.method == "POST":
            urlentry_form = UrlentryForm(request.POST, instance=urlentry, limited_condition=True)
            if urlentry_form.is_valid():
                urlentry = urlentry_form.save(commit=False)
                # additional modification of urlentry, if needed
                urlentry.save()
    else:
        messages.error(request, urlentry_form.errors)
    redirect('polls:detail', pk=urlentry.pk)

#and finalizing code follows here

What worked for me is populating the choices to the form before calling the is_valid() method.

form = CommandSubmitForm(request.POST)
form.fields["unit_id"].choices = choices
if form.is_valid():
  # add your logic here