Handling ForeignKey in Django UpdateView Without Form Display

To handle a ForeignKey in a Django UpdateView without displaying it in the form or extracting it from the URL, you can use one of these approaches:

1. Override form_valid Method

You need to set the ForeignKey value before saving the form:

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def form_valid(self, form):
    # Get the current instance being updated
    instance = self.get_object()
    
    # Set the form's instance person to the current instance's person
    form.instance.person = instance.person
    
    # Continue with the normal form validation process
    return super().form_valid(form)

2. Exclude the Field from the Form

Define a form class that excludes the ForeignKey field:

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class FormularForm(forms.ModelForm):
    class Meta:
        model = Formular
        exclude = ['person']  # Exclude the person field from the form

class FormularUpdateView(UpdateView):
    model = Formular
    form_class = FormularForm
    template_name = 'your_template.html'
    
    def form_valid(self, form):
        # Preserve the existing person relationship
        form.instance.person = self.get_object().person
        return super().form_valid(form)

3. Use a Hidden Field

If you prefer to keep the field in the form but not display it:

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class FormularForm(forms.ModelForm):
    class Meta:
        model = Formular
        fields = ['field1', 'field2', 'person']  # Include all fields
        
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        # Make the person field hidden
        self.fields['person'].widget = forms.HiddenInput()

The first approach is usually the cleanest if you don't want the field in your form at all.