How to set variable maxValue in django forms - django

Question

I'm writing a code in django framework for a sales website and the number of available pieces of a certain merchandise is limited.
to obtain the number of remaining products I have to call a certain function.
Now I wanted to ask if there's any way to call this function in the models.py or forms.py modules or any other way to set this limit.
This is my view module:
from django.http.response import HttpResponse, HttpResponseRedirect
from django.shortcuts import render
from .forms import orderForm
from regpage.models import User
from django.views import View
class orderView(View):
def get(self, request):
form = orderForm()
return render(request, "dashboard/order.html", {'form': form,})
This is my forms module:
from django import forms
from .models import Order
class orderForm(forms.ModelForm):
class Meta:
model = Order
fields = ['productCount']
This is my models module:
from django.db import models
from django.db.models.enums import Choices
from regpage.models import User
from django.core import validators
from django.core.validators import EmailValidator, MaxValueValidator, MinValueValidator
class Order(models.Model):
userID = models.ForeignKey(User, on_delete=models.CASCADE)
productCount = models.PositiveSmallIntegerField() #THE LIMITED FIELD
This is my html file:
{% extends 'dashboard.html' %}
{% block dashTitle %}
Order
{% endblock dashTitle %}
{% block dashContent %}
<p style="text-align:center;font-size:30px;"><b> Order Page </b> </p>
<form style="text-align:center;font-size:25px" method="POST">
{% csrf_token %}
{% for field in form %}
<div class="form-control {% if field.errors %}errors{% endif %}">
{{ field.label_tag }}
{{ field }}
{{ field.errors }}
</div>
<br>
{% endfor %}
<br>
<button type="submit">Order</button>
</form>
{% endblock dashContent %}
There's only one product in this website and one function should be called to obtain the number of remaining products.

Answer 1

Give this a try
class orderForm(forms.ModelForm):
quantity = forms.IntegerField(widget=forms.TextInput(
attrs={
'min':0,
'value':0,
'type':'number',
}))
class Meta:
model = Order
fields = ('__all__')
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self.fields['productCount'].widget.attrs.update(
{'max': self.instance.productCount},
)