Django ManyToMany .add() doesn't add the elements to the created object - django

Question

This is in my template:
<form hx-post="{% url 'orders:create' %}">
{% csrf_token %}
{% for service in venue.services.all %}
<input type="checkbox" name="services" value="{{ service.id }}"> {{ service.name }}<br>
{% endfor %}
<button
hx-include="[name='id']"
type="submit"
class="btn btn-primary btn-lg ">
<input type="hidden" value="{{ venue.id }}" name="id">
Submit
</button>
</form>
And this is the view:
class OrderCreateView(CreateView):
model = Order
form_class = OrderForm
template_name = "orders/order_page.html"
success_url = reverse_lazy("orders:success")
def get_context_data(self, **kwargs):
context = super().get_context_data(**kwargs)
context["venues"] = Venue.objects.all()
return context
def form_valid(self, form):
if self.request.htmx:
# Get the IDs of the chosen services
service_ids = self.request.POST.getlist('services')
# Set the venue field of the form
form.instance.venue = Venue.objects.get(id=self.request.POST.get("id"))
# Save the form
self.object = form.save()
# Add the chosen services to the Order object
for service_id in service_ids:
service = Service.objects.get(id=service_id)
self.object.chosen_services.add(service)
return super().form_valid(form)
The problem is that the object is being created but only the line with form.instance.venue works, the part where the chosen_services are being added doesn't work, the object is created without any of them.
The service_ids variable is populated with the information from the front end, it has the ids that i need, it just doesn't add them to the object.
This is models.py:
class Order(models.Model):
venue = models.ForeignKey(Venue, on_delete=models.SET_NULL, null=True)
chosen_services = models.ManyToManyField(Service, null=True, blank=True)

Answer 1

Try this code
Here m2m field is already handled by form, you need to just set the value of the venue field with save() method of form
def form_valid(self, form):
if self.request.htmx:
# Get the IDs of the chosen services
service_ids = self.request.POST.getlist('services')
fm = form.save()
# Set the venue field of the form
fm.venue = Venue.objects.get(id=self.request.POST.get("id"))
fm.save()
return super().form_valid(form)

Answer 2

The problem was that in forms.py i had this:
class OrderForm(forms.ModelForm):
class Meta:
model = Order
fields = ["chosen_services"]
I deleted that and now it works!