Passing additional form field from HTML to view in Django - django

Question

I was following the post, when I try to solve my solution but it doesn't work for me.
My problem:
I have Django Model object with 4 attributes.
Let's say I have something like this
class MyModel(models.Model):
user = models.ForeignKey('auth.User', on_delete=models.CASCADE)
first_at = models.IntegerField()
second_at = models.IntegerField()
third = models.TextField()
Then I have some view in which I would like to present the form with this object. But, I would like the user to only insert 2 of them, user and the third parameter need to be filled automatically; user from current user and third from another HTML element (in which row the form was filled).
class HomePage(LoginRequiredMixin, generic.CreateView):
template_name = 'index.html'
model = MyModel
fields = ('first', 'second')
success_url = reverse_lazy('home')
def form_valid(self, form):
self.object = form.save(commit=False)
self.object.user = self.request.user
self.object.save()
return super().form_valid(form)
Then I have in HTML created
<form action="." method="POST">
{% csrf_token %}
{{ form.as_p }}
<input type="hidden" name="third" value="{{ item.third }}" />
<input type="submit" value="submit" />
</form>
Does anyone know why this is not working? And or how should I make it work? Is there is a better way?
Marko

Answer 1

You can try this approach
Create a custom form under a forms.py and exclude the fields let's say
class UserForm(forms.ModelForm):
class Meta:
model=Mymodel
exclude = ['user','third']
and in your create view import the form recenlty created and the use it into the CreateView with form_clas
class HomePage(LoginRequiredMixin, generic.CreateView):
form_class = UserForm
template_name = 'index.html'
model = MyModel
fields = ('first', 'second')
success_url = reverse_lazy('home')

Answer 2

I found the solution,
The problem is, that when you use the generic.CreateView and set either fields, or form_class, then this class will only read those fields. Even if you add manually additional input field it will not be passed inside class.
To solve this problem I created form class with hidden field.
class MyForm(forms.ModelForm):
class Meta:
model = models.OrderDetail
fields = ('first', 'second', 'third')
widgets = {
'third' : forms.HiddenInput(),
}
Then I use this form as normal inside view class
class HomePage(LoginRequiredMixin, generic.CreateView):
template_name = 'index.html'
model = MyModel
form_class = forms.MyForm
success_url = reverse_lazy('home')
Then add additional hidden field inside HTML file
<form action="." method="POST">
{% csrf_token %}
{{ form.as_p }}
<input type="hidden" name="third" value="someValue" />
<button type="submit" name="_submit" class="btn btn-raised btn-primary">Submit</button>
</form>
This way, you replace your hidden field that come with form.as_p with custom one.
Note: You don't really replace field. If you inspect the code, you will see, that you will have 2 hidden fields, but only one with value. But because both are hidden, no one could add value to another, so the behaviour is the same as the field would be replaced.