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django Admin - Filter foreign key select depending on other choice in edit form (without jQuery)

I am working on a project which is administered by a super admin who puts in data for different companies.
Lets say, I have these models:
class Company(models.Model):
name = models.CharField(max_length=100)
class ContactPerson(models.Model):
name = models.CharField(max_length=100)
company = models.ForeignKey(Company)
class Item(models.Model):
company = models.ForeignKey(Company)
contact_person = models.ForeignKey(ContactPerson)
I need to ensure that I (in django admin) in the edit mode I only see contact persons which belong to the selected company.
Being not in the year 2005 anymore I want to avoid writing loads of super ugly jQuery code.
I guess I could overwrite the admin form for Item. But still I had to make the contact_person optional, so when I create a new Item, the list of contact persons need to be empty. Then I'd select a company, save it and go back to edit. Now the contact_person list would be filled and I could add somebody. But if I now change the comany, I'd have to remove all selected contact persons. Sure, I could to this in the form... but it looks SO hacky and not like a nice django solution.
Anybody got some fancy ideas?

Actually, django provided me with a neat solution.
When you look at the UserAdmin class within the django code, you'll find a built-in way to handle a two-step creation process.
#admin.register(User)
class UserAdmin(admin.ModelAdmin):
...
add_form = UserCreationForm
...
def get_form(self, request, obj=None, **kwargs):
"""
Use special form during user creation
"""
defaults = {}
if obj is None:
defaults['form'] = self.add_form
defaults.update(kwargs)
return super().get_form(request, obj, **defaults)
When the attribute add_form is set and the object has no id yet (= we are creating it), it takes a different form than usual.
I wrapped this idea in an admin mixin like this:
class AdminCreateFormMixin:
"""
Mixin to easily use a different form for the create case (in comparison to "edit") in the django admin
Logic copied from `django.contrib.auth.admin.UserAdmin`
"""
add_form = None
def get_form(self, request, obj=None, **kwargs):
defaults = {}
if obj is None:
defaults['form'] = self.add_form
defaults.update(kwargs)
return super().get_form(request, obj, **defaults)
Now, when I have dependent fields, I create a small form, containing all values independent of - in my case - company and a regular form containing everything.
#admin.register(Item)
class ItemAdmin(AdminCreateFormMixin, admin.ModelAdmin):
form = ItemEditForm
add_form = ItemAddForm
...
Now I can customise the querysets of the dependent field in my edit form:
class ItemEditForm(forms.ModelForm):
class Meta:
model = Item
exclude = ()
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self.fields['contact_person'].queryset = ContactPerson.objects.filter(company=self.instance.company)
The only drawback is, that all dependent fields need to be nullable for the database. Otherwise you wouldn't be able to save it in the creation process.
Luckily, you can tell django that a field is required in the form but not on database level with blank=False, null=True in the model declaration.
Hope this helps somebody else as well!

Django How can I save two different class which are connected each other by OneToOne relationship in a form at once?

Let me explain what my problem is in more detail.
First I have a class 'UserInfo' which connected to User class of django.contrib.auth.models like below
models.py
class UserInfo(models.Model):
user = models.OneToOneField(User, on_delete=models.CASCADE)
phone = models.CharField(max_length=15,blank=True,unique=True)
position = models.CharField(max_length=15,blank=True,unique=True)
class Meta:
default_permissions = ()
def __str__(self):
return self.position
then I wanted to use ModelForm because I can write less codes. The reason why I made CreateNewUser class is that I wanted to let user can see only [username, email, groups, user_permissions] and control those. (to prevent them to select superuser or staff or inactive options)
forms.py
class CreateNewUserInfo(forms.ModelForm):
class Meta:
model = UserInfo
fields = '__all__'
class CreateNewUser(forms.ModelForm):
class Meta:
model = User
fields = ['username', 'email', 'groups', 'user_permissions']
problem happened in here. I wanted to use FormView to use generic view with class typed view so that I can write less codes(concise code). there is attribute named 'form_class' and I couldn't put two different class with it. I wanted to put different two class to one form with generic view.
views.py
class TestView(FormView):
form_class = CustomForm
template_name = 'manager/alltoall.html'
def form_valid(self, form):
At the end, I made new class in forms.py and wrote every field which I need like below.
forms.py
class CustomForm(forms.Form):
username = forms.CharField(initial='testname',max_length=150)
email = forms.EmailField()
phone_number = forms.CharField(max_length=15)
position = forms.CharField(max_length=15)
views.py
class TestView(FormView):
form_class = CustomForm
template_name = 'manager/alltoall.html'
def form_valid(self, form):
username = form.cleaned_data['username']
email = form.cleaned_data['email']
phone_number = form.cleaned_data['phone_number']
position = form.cleaned_data['position']
with transaction.atomic():
user = User.objects.create(username=username,email=email)
userinfo = UserInfo.objects.create(user=user,phone=phone_number,position=position)
userinfo.save()
user.save()
return super(TestView, self).form_valid(form)
Is there anyway to use ModelForm and FormView to show two different class in a form at the same time? Additionally, I used transaction like above because I wanted to save data in database with two different class. Is it right approach or Is there any other way to do that more conveniently(or efficiently) with built in functions in django?
Thank you for taking your time to read all. I wonder if it is too long, but I wanted to deliver what I wanted to know exactly. Thank you!

Django ModelChoiceField has no plus button

I'm making a Django app with custom users. I've outlined the key components of my problem below, missing code is denoted by '...'. My custom user model has a foreign key relationship as follows:
class MyCustomUser(models.AbstractBaseUser, models.PermissionsMixin)
...
location = models.ForeignKey(Location)
class Location(models.Model)
name = models.CharField(max_length=50, blank=True, null=True)
I've written a custom user form that includes this field as follows:
class MyCustomUserCreationForm(models.ModelForm)
...
location = forms.ModelChoiceField(Location.objects.all())
This all appears to be working correctly, however, there is no plus button to the right of the select field for location. I want to be able to add a location when I create a user, in the same way that you can add polls when creating choices in the Django tutorial. According to this question, I might not see the green plus if I don't have permission to change the model, but I am logged in as a superuser with all permissions. Any idea what I'm doing wrong?

You need to set a RelatedFieldWidgetWrapper wrapper in your model form:
The RelatedFieldWidgetWrapper (found in django.contrib.admin.widgets)
is used in the Admin pages to include the capability on a Foreign Key
control to add a new related record. (In English: puts the little green plus sign to the right of the control.)
class MyCustomUserCreationForm(models.ModelForm)
...
location = forms.ModelChoiceField(queryset=Location.objects.all())
def __init__(self, *args, **kwargs):
super(MyCustomUserCreationForm, self).__init__(*args, **kwargs)
rel = ManyToOneRel(self.instance.location.model, 'id')
self.fields['location'].widget = RelatedFieldWidgetWrapper(self.fields['location'].widget, rel, self.admin_site)
I could make a mistake in the example code, so see these posts and examples:
RelatedFieldWidgetWrapper
More RelatedFieldWidgetWrapper – My Very Own Popup
Django admin - How can I add the green plus sign for Many-to-many Field in custom admin form
How can I manually use RelatedFieldWidgetWrapper around a custom widget?
Django: override RelatedFieldWidgetWrapper

I have created method based on the answers above:
def add_related_field_wrapper(form, col_name):
rel_model = form.Meta.model
rel = rel_model._meta.get_field(col_name).rel
form.fields[col_name].widget =
RelatedFieldWidgetWrapper(form.fields[col_name].widget, rel,
admin.site, can_add_related=True, can_change_related=True)
And then calling this method from my form:
class FeatureForm(forms.ModelForm):
offer = forms.ModelChoiceField(queryset=Offer.objects.all(), required=False)
package = forms.ModelChoiceField(queryset=Package.objects.all(), required=False)
def __init__(self, *args, **kwargs):
super(FeatureForm, self).__init__(*args, **kwargs)
add_related_field_wrapper(self, 'offer')
add_related_field_wrapper(self, 'package')
That works fine on Django 1.8.2.

Google pointed me to this page when searching how to get a "+" icon next to fields in a custom form with ForeignKey relationship, so I thought I'd add.
For me, using django-autocomplete-light did the trick very well, using the "add another" functionality.

You don't even need to go that far, and besides, these answers are probably outdated as NONE of them worked for me in any capacity.
What I did to solve this is, as long as you have the ForeignKey field already in your model, then you can just create your custom ModelChoiceField:
class LocationModelChoiceField(forms.ModelChoiceField):
def label_from_instance(self, obj):
return "%" % (obj.name)
The key next is NOT to create a custom field for the ModelChoiceField in your ModelForm (ie location = forms.ModelChoiceField(Location.objects.all()))
In other words, leave that out and in your ModelForm have something like this:
class UserAdminForm(forms.ModelForm):
class Meta:
model = User
fields = '__all__'
Lastly, in your ModelAdmin:
class UserAdmin(admin.ModelAdmin):
model = User
form = UserAdminForm
def formfield_for_foreignkey(self, db_field, request, **kwargs):
if db_field.name == 'location':
return LocationModelChoiceField(queryset=Location.objects.order_by('name')) # if you want to alphabetize your query
return super().formfield_for_foreignkey(db_field, request, **kwargs)

Alternative Method : Using .remote_field instead of rel
def add_related_field_wrapper(self,form, col_name):
rel_model = form.Meta.model
rel = rel_model._meta.get_field(col_name).remote_field
form.fields[col_name].widget = RelatedFieldWidgetWrapper(form.fields[col_name].widget, rel, admin.site, can_add_related=True, can_change_related=True)
def __init__(self, *args, **kwargs):
super(CustomerAdminForm, self).__init__(*args, **kwargs)
self.add_related_field_wrapper(self, 'offer')
self.add_related_field_wrapper(self, 'package')
Thankyou,

Modifying a Django ModelForms fields

I have a Django model, which has a foreign key owner, referring to the user who owns this object.
To let other users edit these objects, I currently use a forms.ModelForm, which works fine so far.
But I know want to let the owner and only the owner change the owner of the object he owns (what an ownage! :). Thus I tried the following:
class FolderForm(forms.ModelForm):
def __init__(self, user, *args, **kwargs):
if kwargs.get("instance", False):
if user == kwargs["instance"].owner:
self._meta.fields += ("owner",)
super(FolderForm, self).__init__(*args, **kwargs)
class Meta:
model = Folder
fields = (
"name",
"description",
)
But this doesn't work, since Django uses some metaclass-magic to set the fields on the model, which seems to be done before my subclassed __init__ is called.
Anyone ever did something like this?

I like to use closure normally
def make_form(exclude_user=True):
class Form(forms.ModelForm):
class Meta:
model = Folder
exclude = ['user'] if exclude_user else None
return Form
form_cls = make_form(request.user != folder.owner)

Why don't you create two Forms:
One that excludes owner for users that don't own the data (mouthful) and do a simple if statement in your view:
if request.user == Model.owner:
form = OwnerForm
else:
form = OthersForm
Keep it as simple as possible has HUGE wins down the line.

How to pass initial parameter to django's ModelForm instance?

The particular case I have is like this:
I have a Transaction model, with fields: from, to (both are ForeignKeys to auth.User model) and amount. In my form, I'd like to present the user 2 fields to fill in: amount and from (to will be automaticly set to current user in a view function).
Default widget to present a ForeignKey is a select-box. But what I want to get there, is limit the choices to the user.peers queryset members only (so people can only register transactions with their peers and don't get flooded with all system users).
I tried to change the ModelForm to something like this:
class AddTransaction(forms.ModelForm):
from = ModelChoiceField(user.peers)
amount = forms.CharField(label = 'How much?')
class Meta:
model = models.Transaction
But it seems I have to pass the queryset of choices for ModelChoiceField right here - where I don't have an access to the web request.user object.
How can I limit the choices in a form to the user-dependent ones?

Use the following method (hopefully it's clear enough):
class BackupForm(ModelForm):
"""Form for adding and editing backups."""
def __init__(self, *args, **kwargs):
systemid = kwargs.pop('systemid')
super(BackupForm, self).__init__(*args, **kwargs)
self.fields['units'] = forms.ModelMultipleChoiceField(
required=False,
queryset=Unit.objects.filter(system__id=systemid),
widget=forms.SelectMultiple(attrs={'title': _("Add unit")}))
class Meta:
model = Backup
exclude = ('system',)
Create forms like this:
form_backup = BackupForm(request.POST,
instance=Backup,
systemid=system.id)
form_backup = BackupForm(initial=form_backup_defaults,
systemid=system.id)
Hope that helps! Let me know if you need me to explain more in depth.

I ran into this problem as well, and this was my solution:
class ChangeEmailForm(forms.ModelForm):
def __init__(self, user, *args, **kwargs):
self.user = user
super(ChangeEmailForm, self).__init__(*args, **kwargs)
self.fields['email'].initial = user.email
class Meta:
model = User
fields = ('email',)
def save(self, commit=True):
self.user.email = self.cleaned_data['email']
if commit:
self.user.save()
return self.user

Pass the user into the __init__ of the form, and then call super(…). Then set self.fields['from'].queryset to user.peers