How to change the widget of the field?

[alokRamteke]

Right now, by default we have CheckboxSelectMultiple widget for the MultiSelectField.
How can I change it to SelectMultiple and show it by default?
Do I need to pass any parameter in model-field?

Right now, I am following below method to override it in the models. Let me know, if we have any better way?

from django.utils.text import capfirst
from multiselectfield import MultiSelectField
from multiselectfield.forms.fields import MultiSelectFormField

class MultiSelectDropdownFormField(MultiSelectFormField):
    widget = forms.SelectMultiple


class MultiSelectDropdownField(MultiSelectField):
    def formfield(self, **kwargs):
        defaults = {'required': not self.blank,
                    'label': capfirst(self.verbose_name),
                    'help_text': self.help_text,
                    'choices': self.choices,
                    'max_length': self.max_length,
                    'max_choices': self.max_choices}
        if self.has_default():
            defaults['initial'] = self.get_default()
        defaults.update(kwargs)
        return MultiSelectDropdownFormField(**defaults)


field = MultiSelectDropdownField(max_length=30, choices=CHOICES)

[LukasKlement]

I've just written a comment on how to display a field using the multi select field in the Django Admin using the PostgreSQL ArrayField: #124