[Django]-Django ModelChoiceField: filtering query set and setting default value as an object

by

114👍

✅

Override the init method and accept a new keyword argument

class AccountDetailsForm(forms.Form):
    ...
    adminuser = forms.ModelChoiceField(queryset=User.objects.all())
    def __init__(self, *args, **kwargs):
        accountid = kwargs.pop('accountid', None)
        super(AccountDetailsForm, self).__init__(*args, **kwargs)

        if accountid:
            self.fields['adminuser'].queryset = User.objects.filter(account=accountid)

form = AccountDetailsForm(accountid=3)

You can always just set the choices manually in the view as well.

form = AccountDetailsForm()
form.fields['adminuser'].queryset = User.objects.filter(account=accountid)

Be warned: you are not setting default values by passing in a dictionary to a form like in your example.

You are actually creating a Bound Form, potentially triggering validation and all that jazz.

To set defaults, use the initials argument.

form = AccountDetailsForm(initial={'adminuser':'3'})
👤Yuji 'Tomita' Tomita

6👍

You can override the field in the view

yourForm = AccountDetailsForm()

yourForm.fields['accomodation'] = forms.ModelChoiceField(User.objects.filter(account=accountid).filter(primary_user=1))
👤Willians Vivanco

1👍

Something that hasn’t been mentioned here yet is the Form.clean() method. This method is specifically for custom validation.

For your example, you could do something like this:

class AccountDetailsForm(forms.Form):
    adminuser = forms.ModelChoiceField(queryset=User.objects.all())
    account_id = forms.IntegerField()  # or ModelChoiceField if that applies

    def clean(self):
        account_id = self.cleaned_data['account_id']
        self.cleaned_data['adminuser'] = User.objects.filter(account_id=account_id)

    return self.cleaned_data

The clean() method gets called after the default clean methods, so you can use self.cleaned_data (same as form.cleaned_data in the view) and return it however you’d like.

Even better, you can name the method according to the field you’d like to clean (def clean_adminuser) and make easier to read.

def clean_adminuser(self):
    account_id = self.cleaned_data['account_id']
    return User.objects.filter(account_id=account_id)

Also in this method you can call Form.add_error() if there are any issues you want to handle.

👤zackcpetersen

0👍

In Django 2.0 you can pass object (User in your case) from the view to the form like this (you have to retrieve obj from the DB first):

form = AccountDetailsForm(initial={'adminuser': adminuser})

It will give you a default selected object (answers your 2) question)

👤techkuz

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