How to change the value of a field in a form?

Question

Django

Hello!
I use JSONField , it stores data as a list ["123", "345", "test"], field oem_list .
When editing in the field, the data is in json ["123", "345", "test"], but you need it to be just comma-separated 123, 345, test!
How to change the data in the format I need, I try self.fields['oem_list'].initial, doesn't work?!

class QueryForm(forms.ModelForm):
    oem_list = forms.CharField(label=u'OEM номера', required=False)

    def __init__(self, user, *args, **kwargs):
        super(QueryForm, self).__init__(*args, **kwargs)
        self.fields['oem_list'].initial = u"Значение поля заменено" # не работает

    class Meta:
        model = Query

    def clean_oem_list(self):
        data = self.cleaned_data['oem_list'].upper()

        if data and ',' in data:
            data = list(set(x for x in data.split(',') if x))
        elif data:
            data = [data]

        return data

Answer 1

Somehow strange you load json. First, try to do it right:

import json
.....
self.fields['oem_list'].initial = json.dumps(ваше поле с json).replace('"','')[1:-1]
.....
data = json.loads(self.cleaned_data['oem_list'])

Answer 2

You can write your own widget, override the render and value_from_datadict methods in it, and explicitly set oem_list for the field.

Answer 3

Why use a JSON field to store a list? Get ArrayField from djorm_pgarray if you have PostgreSQL.