# Cannot assign, Must be an instance Error

**URL:** <https://forum.djangoproject.com/t/cannot-assign-must-be-an-instance-error/26352>\
**Category:** Mystery Errors\
**Created:** [December 22, 2023, 7:05am UTC](https://forum.djangoproject.com/t/cannot-assign-must-be-an-instance-error/26352 "2023-12-22T07:05:35Z")\
**Posts on this page:** 8\
**Page:** 1

<div class="post-metadata">

**Author:** ![MaykCheck](https://sea2.discourse-cdn.com/flex026/user_avatar/forum.djangoproject.com/maykcheck/32/17462_2.png) [@MaykCheck](https://forum.djangoproject.com/u/MaykCheck)\
**Post date:** [December 22, 2023, 7:05am UTC](https://forum.djangoproject.com/t/cannot-assign-must-be-an-instance-error/26352/1 "2023-12-22T07:05:36Z")

</div>

Hello everyone I am keep getting this error and I don’t understand why, I want to send an email with django when user fills out the form and I want to select recipents with the form, I made a model form and when I try to select recipents I get the error. Here is my code:

models.py:

```auto
class State(models.Model):
    profile = models.ForeignKey(Profile, on_delete=models.CASCADE)
    country = models.CharField(max_length=100)
    capital = models.CharField(max_length=100)
    president = models.ManyToManyField(President)
    city = models.ManyToManyField(Cities)
    date = models.DateTimeField()
    slug = models.SlugField(unique=True)

    def save(self, *args, **kwargs):
        self.slug = slugify(self.country)
        super(State, self).save(*args, **kwargs)

    def __str__ (self):
        return self.country
    
    def get_absolute_url(self):
        return reverse('mailapp2:details', args=[self.slug])
    

```

and my profile model has user object which has OneToOne relation with the django’s User model,

forms.py:

```auto
class StateForm(forms.ModelForm):
    city = forms.ModelMultipleChoiceField(queryset=Cities.objects.all(), required=True)
    president= forms.ModelMultipleChoiceField(queryset=President.objects.all(), required=True)
    profile = forms.ModelMultipleChoiceField(queryset=Profile.objects.all(), required=True)
    class Meta:
        model = State
        fields = ('country','capital','city', 'date', 'president','profile')
        widgets = {
            'country':forms.TextInput(attrs={"placeholder":"Country", "required":"True", "style":"width:40%;"}),
            'capital':forms.TextInput(attrs={"placeholder":"Capital", "required":"True", "style":"width:40%;"}),
            'city':forms.CheckboxSelectMultiple(attrs={"placeholder":"choose a city"}),
            'date':forms.DateTimeInput(attrs={"type":"text", "onfocus":"(this.type='datetime-local')","placeholder":"Date","id":"date"}),
            'president':forms.CheckboxSelectMultiple(attrs={"placeholder":"President","class":"katılımcıselect"}),
            'profile':forms.CheckboxSelectMultiple(attrs={"placeholder":"Recipents","class":"recipentselect"}),
        }
        labels = {
            'country':'country',
            'capital':'capital',
            'city':'city',
            'date':'date',
            'president':'president',
            'profile':'profile'
        }

```

(this is a dummy project to understand how django’s email backend works so the object’s names are pointless)

and my views.py:

```auto
def addState(request):
    if request.method == 'POST':
        form = StateForm(data=request.POST)
        if form.is_valid():
            date = form.cleaned_data['date']
            city= form.cleaned_data['city']
            profile = form.cleaned_data['profile']
            new_state = form.save(commit=False)
            user_profile = Profile.objects.get(user=request.user)
            new_state.profile = user_profile
            new_state.save()
            form.save_m2m()

            template = render_to_string('mailapp2/email.html', {
                                            'name':request.user.username,
                                            'date':date,
                                            'city':city,
                                            'profile':profile
                                            })
            plain_message = strip_tags(template)

            email = EmailMessage(
                'State Notification',
                plain_message,
                settings.EMAIL_HOST_USER,
                [profile.user.email], 
            )
            email.fail_silently=False
            email.send()            

            return redirect('http://127.0.0.1:8000/')
        else:
            print(form.errors)
    else:
        form = StateForm(data=request.GET)
    return render(request, 'mailapp2/add_state.html',{
        'form':form
    })

```

I cannot see where is my problem, thank you from now 🙂  
PS. I translated its language so there may be little spelling errors but it is working in main project, this is why all objects are silly

---

<div class="post-metadata">

**Author:** ![KenWhitesell](https://sea2.discourse-cdn.com/flex026/user_avatar/forum.djangoproject.com/kenwhitesell/32/280_2.png) [@KenWhitesell](https://forum.djangoproject.com/u/KenWhitesell)\
**Post date:** [December 22, 2023, 1:14pm UTC](https://forum.djangoproject.com/t/cannot-assign-must-be-an-instance-error/26352/2 "2023-12-22T13:14:00Z")

</div>

> [@MaykCheck](#):
>
> ```auto
> email.fail_silently=False
> email.send()            
> 
> ```

This is not the syntax for that. It should be `email.send(fail_silently=False)`

See the docs at [Sending email | Django documentation | Django](https://docs.djangoproject.com/en/5.0/topics/email/#emailmessage-objects)

---

<div class="post-metadata">

**Author:** ![MaykCheck](https://sea2.discourse-cdn.com/flex026/user_avatar/forum.djangoproject.com/maykcheck/32/17462_2.png) [@MaykCheck](https://forum.djangoproject.com/u/MaykCheck)\
**Post date:** [December 25, 2023, 5:24am UTC](https://forum.djangoproject.com/t/cannot-assign-must-be-an-instance-error/26352/3 "2023-12-25T05:24:34Z")

</div>

> ```
> email.fail_silently=False
> email.send()
> 
> ```

this was working until I add

> profile = form.cleaned\_data[‘profile’]

it is saying it must be Profile instance but I am trying to render Profile instance

> email = EmailMessage(  
> Toplantı Bildirimi’,  
> plain\_message,  
> settings.EMAIL\_HOST\_USER,  
> devlet.profile.user.email]

I am sorry I forgot the show the actual error code.

```auto
ValueError at /addState/
Cannot assign "<QuerySet [<Profile: profile1>, <Profile: profile2>, <Profile: profile3>]>": "State.profile" must be a "Profile" instance.

```

---

<div class="post-metadata">

**Author:** ![KenWhitesell](https://sea2.discourse-cdn.com/flex026/user_avatar/forum.djangoproject.com/kenwhitesell/32/280_2.png) [@KenWhitesell](https://forum.djangoproject.com/u/KenWhitesell)\
**Post date:** [December 25, 2023, 5:57am UTC](https://forum.djangoproject.com/t/cannot-assign-must-be-an-instance-error/26352/4 "2023-12-25T05:57:40Z")

</div>

Please post the _complete_ traceback.

---

<div class="post-metadata">

**Author:** ![MaykCheck](https://sea2.discourse-cdn.com/flex026/user_avatar/forum.djangoproject.com/maykcheck/32/17462_2.png) [@MaykCheck](https://forum.djangoproject.com/u/MaykCheck)\
**Post date:** [December 25, 2023, 6:04am UTC](https://forum.djangoproject.com/t/cannot-assign-must-be-an-instance-error/26352/5 "2023-12-25T06:04:15Z")

</div>

there might be language difference in the objects that I can not see in the traceback

```auto
Environment:

Request Method: POST
Request URL: http://127.0.0.1:8000/devlet_ekle/

Django Version: 4.2.6
Python Version: 3.12.1
Installed Applications:
['mailapp2',
 'django.contrib.admin',
 'django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.messages',
 'django.contrib.staticfiles']
Installed Middleware:
['django.middleware.security.SecurityMiddleware',
 'django.contrib.sessions.middleware.SessionMiddleware',
 'django.middleware.common.CommonMiddleware',
 'django.middleware.csrf.CsrfViewMiddleware',
 'django.contrib.auth.middleware.AuthenticationMiddleware',
 'django.contrib.messages.middleware.MessageMiddleware',
 'django.middleware.clickjacking.XFrameOptionsMiddleware']

Traceback (most recent call last):
  File "C:\Users\TP054591\AppData\Local\Programs\Python\Python312\Lib\site-packages\django\core\handlers\exception.py", line 55, in inner
    response = get_response(request)
               ^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\TP054591\AppData\Local\Programs\Python\Python312\Lib\site-packages\django\core\handlers\base.py", line 197, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\TP054591\Desktop\Taha Polat Projeler\AralıkProjeleri\211223Proje\mailapp2\views.py", line 80, in devlet_ekle
    if form.is_valid():
       ^^^^^^^^^^^^^^^
  File "C:\Users\TP054591\AppData\Local\Programs\Python\Python312\Lib\site-packages\django\forms\forms.py", line 201, in is_valid
    return self.is_bound and not self.errors
                                 ^^^^^^^^^^^
  File "C:\Users\TP054591\AppData\Local\Programs\Python\Python312\Lib\site-packages\django\forms\forms.py", line 196, in errors
    self.full_clean()
    ^^^^^^^^^^^^^^^^^
  File "C:\Users\TP054591\AppData\Local\Programs\Python\Python312\Lib\site-packages\django\forms\forms.py", line 435, in full_clean
    self._post_clean()
    ^^^^^^^^^^^^^^^^^^
  File "C:\Users\TP054591\AppData\Local\Programs\Python\Python312\Lib\site-packages\django\forms\models.py", line 479, in _post_clean
    self.instance = construct_instance(
                    
  File "C:\Users\TP054591\AppData\Local\Programs\Python\Python312\Lib\site-packages\django\forms\models.py", line 83, in construct_instance
    f.save_form_data(instance, cleaned_data[f.name])
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\TP054591\AppData\Local\Programs\Python\Python312\Lib\site-packages\django\db\models\fields\ __init__.py", line 1035, in save_form_data
    setattr(instance, self.name, data)
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\TP054591\AppData\Local\Programs\Python\Python312\Lib\site-packages\django\db\models\fields\related_descriptors.py", line 266, in __set__
    raise ValueError(
    ^

Exception Type: ValueError at /devlet_ekle/
Exception Value: Cannot assign "<QuerySet [<Profile: profile1>, <Profile: profile2>, <Profile: profile3>]>": "State.profile" must be a "Profile" instance.

```

---

<div class="post-metadata">

**Author:** ![KenWhitesell](https://sea2.discourse-cdn.com/flex026/user_avatar/forum.djangoproject.com/kenwhitesell/32/280_2.png) [@KenWhitesell](https://forum.djangoproject.com/u/KenWhitesell)\
**Post date:** [December 25, 2023, 6:10am UTC](https://forum.djangoproject.com/t/cannot-assign-must-be-an-instance-error/26352/6 "2023-12-25T06:10:59Z")

</div>

So, notice that the error in your code is occurring here:

> [@MaykCheck](#):
>
> ```auto
> File "C:\Users\TP054591\Desktop\Taha Polat Projeler\AralıkProjeleri\211223Proje\mailapp2\views.py", line 80, in devlet_ekle
> if form.is_valid():
> ^^^^^^^^^^^^^^^
> 
> ```

You’re binding the data to the form here:

> [@MaykCheck](#):
>
> `form = StateForm(data=request.POST)`

which means you’re submitting something in the form that can’t be bound to the model.

Further down in the traceback it shows:

> [@MaykCheck](#):
>
> `"State.profile" must be a "Profile" instance.`

telling us which field is causing the problem.

Your definition of `profile` in `State` is this:

> [@MaykCheck](#):
>
> `profile = models.ForeignKey(Profile, on_delete=models.CASCADE)`

This means that the `profile` field contains a reference to **one** instance of `Profile`.

However, you have your form defined as:

> [@MaykCheck](#):
>
> `profile = forms.ModelMultipleChoiceField(queryset=Profile.objects.all(), required=True)`

Which would allow the user to select multiple instances of `Profile` - but that’s not valid for your model.

Your form’s `profile` field would need to be a `ModelChoiceField`, **not** a `ModelMultipleChoiceField`.

---

<div class="post-metadata">

**Author:** ![MaykCheck](https://sea2.discourse-cdn.com/flex026/user_avatar/forum.djangoproject.com/maykcheck/32/17462_2.png) [@MaykCheck](https://forum.djangoproject.com/u/MaykCheck)\
**Post date:** [December 25, 2023, 6:20am UTC](https://forum.djangoproject.com/t/cannot-assign-must-be-an-instance-error/26352/7 "2023-12-25T06:20:02Z")

</div>

so if I change

> profile = models.ForeignKey(Profile, on\_delete=models.CASCADE)

by:

> profile = models.ManyToManyField(Profile, on\_delete=models.CASCADE)

then can I use ModelMultipleChoiceField for selecting multiple profiles to send mail?

---

<div class="post-metadata">

**Author:** ![KenWhitesell](https://sea2.discourse-cdn.com/flex026/user_avatar/forum.djangoproject.com/kenwhitesell/32/280_2.png) [@KenWhitesell](https://forum.djangoproject.com/u/KenWhitesell)\
**Post date:** [December 25, 2023, 2:48pm UTC](https://forum.djangoproject.com/t/cannot-assign-must-be-an-instance-error/26352/8 "2023-12-25T14:48:49Z")

</div>

Yes, that would work.

Additionally, see the notes regarding save with `commit=False` and using the `save_m2m` method in the docs at [Creating forms from models | Django documentation | Django](https://docs.djangoproject.com/en/5.0/topics/forms/modelforms/#the-save-method)