Django Form with Select2 Widget and Dynamic City Creation

There are several issues with your current implementation that need to be addressed. Let me analyze your code and suggest improvements:

Issues and Improvements

1. Model Confusion

You have two City models:

• cities_light.City (used in the Event model's foreign key)
• Your custom City model (imported as CityModel)

This creates confusion in your code. Your Event model references cities_light.City but your form tries to create instances of your custom CityModel.

2. Clean Method Issues

Your clean_venue_city method has several problems:

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def clean_venue_city(self):
    city_input = self.cleaned_data['venue_city'].strip()
    
    # This query is incorrect - venue_city is a ForeignKey, not a text field
    city = Event.objects.filter(venue_city__iexact=city_input).first()
    
    # ...rest of the method

The venue_city field will be an object, not a string, so calling .strip() will cause an error.

3. Widget Configuration

Your CityWidget is looking for a field called name but your model has city_name:

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class CityWidget(s2forms.ModelSelect2TagWidget):
    search_fields = [
        'name__istartswith'  # Should be 'city_name__istartswith'
    ]

Corrected Implementation

Here's a corrected implementation:

PYTHONCopied
from django import forms
from django.forms import ModelForm
from cities_light.models import City as CitiesLightCity
from .models import Event
from django_select2 import forms as s2forms
from django_select2.forms import ModelSelect2TagWidget

class CityWidget(s2forms.ModelSelect2TagWidget):
    search_fields = [
        'name__istartswith'  # Assuming cities_light.City has a 'name' field
    ]
    
    def create_value(self, value):
        """Create a new city if it doesn't exist"""
        # This method is called when a new tag is created
        # Return the primary key of the newly created object
        city, created = CitiesLightCity.objects.get_or_create(name=value)
        return city.pk

class EventForm(forms.ModelForm):
    class Meta:
        model = Event
        exclude = ['creator', 'artist', 'id']
        widgets = {
            'venue_city': CityWidget,
            # other widgets...
        }
    
    def save(self, commit=True):
        event = super().save(commit=False)
        
        # No need to manually set venue_city as ModelForm handles it
        
        if commit:
            event.save()
        
        return event

Key Recommendations

1. Decide on one City model: Either use cities_light.City consistently or your custom City model, but not both.

2. Use the widget's built-in tag creation: The ModelSelect2TagWidget has built-in functionality for creating new options. Override the create_value method to handle new city creation.

3. Remove unnecessary clean method: If you're using the widget's tag creation functionality, you don't need a custom clean method.

4. Check field names: Make sure the search fields in your widget match the actual field names in your model.

5. Consider using a custom queryset: You might want to add a queryset attribute to your widget to control which cities are available in the dropdown.

This approach will provide a cleaner implementation that properly handles both selecting existing cities and creating new ones when needed.