ModelMultipleChoiceField - override validation

[Earl Lapus]

Hi,

I have a ModelForm that has a ModelMultipleChoiceField. In the said field, I've set the queryset to none and assigned the FilteredSelectMultiple as the widget for the field.

It looks like this:

class MyForm(forms.ModelForm):

    myfield = ModelMultipleChoiceField(

        queryset=SomeModel.objects.none(),

        widget=admin.widgets.FilteredSelectMultiple('SomeModel', False),

        required=False

    )

I added some javascript on the template to dynamically add items to the widget based on a value from another field. That part already works. But, I am running into an error during submit - validation error. An example error I get is: "Select a valid choice. 4 is not one of the available choices."  This is expected since I've set the queryset to be empty, so values will match during validation.

Where should I override the validation? I tried creating a ModelMultipleChoiceField child class and implemented the `to_python()` method but it seems like that method is not called. Is there any documentation that can help me arrive at an answer for this?

Cheers,
Earl

[Earl Lapus]

I was able to resolve this by overriding `clean()` instead of `to_python()`. In there, I've the set correct queryset to use for validation.

I still could not explain why `to_python()` is not called.