Making a CreateForm with choices based on database values - django

Question

I am making a django project and I have a form for the User to add a Vehicle Manually that will be assigned to him. I also would like to had an option for the user to choose a vehicle based on the entries already present in the database.
vehicles/models.py
class Vehicle(models.Model):
user = models.ForeignKey(User, on_delete=models.CASCADE)
nickname = models.CharField(unique = True, max_length=150)
date_joined = models.DateTimeField(default=timezone.now)
brand = models.CharField(max_length=150)
battery = models.CharField(max_length=150)
model = models.CharField(max_length=150)
def __str__(self):
return self.nickname
def get_absolute_url(self):
return reverse('vehicle-list')
class Meta:
db_table = "vehicles"
I created a form so the user can add his Vehicles as such:
vehicles/forms.py
class VehicleAddFormManual(forms.ModelForm):
class Meta:
model = Vehicle
fields = ('brand','model', 'battery', 'nickname')
def __init__(self, *args, **kwargs):
user = kwargs.pop('user', None)
super().__init__(*args, **kwargs)
self.fields['brand']
self.fields['model']
self.fields['battery']
self.fields['nickname']
The corresponding view:
vehicles/views.py
class AddVehicleViewManual(LoginRequiredMixin, CreateView):
model = Vehicle
form_class = VehicleAddFormManual
def get_form_kwargs(self):
kwargs = super().get_form_kwargs()
kwargs['user'] = self.request.user
return kwargs
def form_valid(self, form):
form.instance.user = self.request.user
return super().form_valid(form)
The html file:
vehicles/templates/vehicles/vehicle_form.html
{% extends "blog/base.html" %}
{% block content %}
{% load crispy_forms_tags %}
<div class="content-section">
<form method="POST">
{% csrf_token %}
<fieldset class="form-group">
<legend class="border-bottom mb-4">New Vehicle</legend>
{{ form|crispy }}
</fieldset>
<div class="form-group">
<button class="btn btn-outline-info" type="submit">Submit</button>
</div>
</form>
</div>
{% endblock content %}
I would like to add another form in which the user has a dropdown with option with the brands, models and batteries that already exist in the database. If there's a car in the database with brand: Tesla, model: Model 3, battery: 50 kWh, then it would appear in the dropbox as a choice for each field.
I'm not sure how to do this and sorry for the newbie question... Thanks in advance!

Answer 1

I once had to do something similar, but I needed a form which had one checkbox for each item in a list of externally-supplied strings. I don't know if this is the cleanest way, but I used python metaclasses:
class SockSelectForm(forms.Form):
#staticmethod
def build(sock_names):
fields = {'sock_%s' % urllib.parse.quote(name):
forms.BooleanField(label=name, required=False)
for name in sock_names}
sub_class = type('DynamicSockSelectForm', (SockSelectForm,), fields)
return sub_class()
In my get() method, I instantiate it as:
form = SockSelectForm.build(names)
and the corresponding form handling in the post() method is:
form = SockSelectForm(request.POST)
I suspect if you look under the covers of Django's ModelForm, you'd see something similar, but I couldn't use ModelForm because it's too closely tied to the model system for what I needed to do.

Answer 2

model.py
class DropdownModel(models.Model):
brand = models.CharField(max_length=150)
battery = models.CharField(max_length=150)
model = models.CharField(max_length=150)
def __str__(self):
return self.brand.
form.py
from .models import DropdownModel
all_brand = DropdownModel.objects.values_list('brand','brand')
all_battery = DropdownModel.objects.values_list('battery','battery')
all_model= DropdownModel.objects.values_list('model','model')
class DropdownForm(forms.ModelForm):
class Meta:
model = DropdownModel
fields = "__all__"
widgets = {
'brand':forms.Select(choices=all_brand),
'battery':forms.Select(choices=all_battery),
'model':forms.Select(choices=all_model),
}
view.py
from django.shortcuts import render
from .form import DropdownForm
# Create your views here.
def HomeView(request):
form = DropdownForm()
context = {'form':form}
return render(request,'index.html',context)
index.html
{% extends "base.html" %}
{% load static %}
{% block title %}
Index | Page
{% endblock title %}
{% block body %}
{{form.as_p}}
{% endblock body %}
Output-
Note- if u can't see updated values in dropdown do server restart because localhost not suport auto update value fill in dropdown it's supoorted on live server
Thank you