m2m createview bootstrap modal

[Robin Riis]

Hello Django community :D

i am currently learning django and am working on a vehicle app

where i currently have this models.py

class Engine(models.Model):

    objects = EngineManager()

    manufacture = models.CharField(max_length=80)

    name = models.CharField(max_length=80)

    filter_to_use = models.ManyToManyField('Filter') #this is in another app

    class Meta:

        unique_together = (('manufacture', 'name'),)

    def natural_key(self):

        return (self.manufacture, self.name)

    def __unicode__(self):

        return self.__str__()

    def __str__(self):

        return self.manufacture+' - '+self.name

class Vehicle_Model(models.Model):

    engine = models.ForeignKey(Engine, on_delete=models.CASCADE)

    name = models.CharField(max_length=100)

    year_from = models.IntegerField(blank=True, null=True)

    year_to = models.IntegerField(blank=True, null=True)

    serial_number_from = models.CharField(max_length=100, blank=True, null=True)

    serial_number_to = models.CharField(max_length=100, blank=True, null=True)

    picture = models.ImageField(upload_to=modell_picture_path, default='machine_models/none.png')

    ........

and i am trying to create a form for Engine.filter_to_use that will open in a modal

the form currently looks like this:

class AddEngineFilterAjaxForm(PopRequestMixin, CreateUpdateAjaxMixin, forms.ModelForm):

    class Meta:

        model = Engine

        fields = ('filter_to_use',)

        widgets = {'filter_to_use': forms.SelectMultiple(),}

    def __init__(self, *args, **kwargs):

        super(AddEngineFilterAjaxForm, self).__init__(*args, **kwargs)

        self.fields['filter_to_use'].widget.attrs['class'] = 'selectpicker form-control'

        self.fields['filter_to_use'].widget.attrs['data-live-search'] = 'true'

        self.fields['filter_to_use'].widget.attrs['title'] = 'Which filter fits in the engine?'

and i am struggling with the view and right now im pretty lost of all the trial and error :P

but i want it to have pre-selected all filters that are bound to the engine

and i want to be able to save the form.

it does look right, but the behaviour is not what i wanted.

any tips on how to write a class based view for this?

thanks in advance!