[FIXED] many to many field in django is working in admin site but not in front end site form

Issue

In my code CreateNoticeForm is working fine and all data gets saved perfectly except many to many field which is tags in my notice model.Although it is working on admin site and gets saved.

here is my code models.py

from django.db import models
from django.contrib.auth.models import User

from wysihtml5.fields import Wysihtml5TextField

# Create your models here.
class Tag(models.Model):
    # For notice tags
    name = models.CharField(max_length=70, unique=True)

    def __str__(self):
        return self.name


class Notice(models.Model):
    # Notice Store
    headline = models.CharField(max_length=140)
    description = Wysihtml5TextField()
    file_name = models.FileField(upload_to='static/noticefiles/', blank=True)
    created_by = models.ForeignKey(User)
    fors = models.CharField(max_length=1, choices=(('F','Faculty'),('S','Student'),) )
    last_date = models.DateField()
    tags = models.ManyToManyField(Tag, blank=True)
    post_time = models.DateTimeField(auto_now_add=True)
    update_time = models.DateTimeField(auto_now=True)

    def __str__(self):
        return self.headline

forms,py

FORS_CHOICES = (('F','Faculty'),('S','Student'))


class CreateNoticeForm(ModelForm):
    fors = forms.ChoiceField(label="Related To",
                             choices=FORS_CHOICES,
                            )
    class Meta:
        model = Notice
        fields = ('headline', 'description',
                  'fors', 'last_date', 'tags','file_name')
        widgets = {
            'description': Wysihtml5BootstrapWidget(),
            'last_date': SelectDateWidget()
        }
    def __init__(self, *args, **kwargs):
        super(CreateNoticeForm, self).__init__(*args, **kwargs)
        self.helper = FormHelper()
        self.helper.form_id = 'create_notice_form_id'
        self.helper.form_class = 'form-horizontal'
        self.helper.form_method = 'post'
        self.helper.label_class = 'col-lg-2'
        self.helper.field_class = 'col-lg-8'
        self.helper.layout = Layout(
            Fieldset('Create Notice',
                     'headline', 
                     'description',
                     Field('fors', label='Audience'),
                     MultiWidgetField('last_date',
                        attrs=(
                            {'style': 'width: 33.33%; display: inline-block;'}
                        )
                     ),
                     'tags',
                     'file_name',
                     FormActions(
                        Submit('save', 'Create Notice', 
                        css_class='btn-warning col-lg-offset-2'),
                     ),
            ),

views.py

def create_notice(request):

    context = RequestContext(request)

    posted = False

    if request.method=='POST':
        create_notice_form = CreateNoticeForm(data=request.POST, files=request.FILES)

        if create_notice_form.is_valid():
            cnf = create_notice_form.save(commit=False)
            cnf.created_by = request.user
            cnf.save()
            posted = True
        else:
            print(create_notice_form.errors)

    else:
        create_notice_form = CreateNoticeForm()


    return render_to_response('notices/createnotice1.html',
                              {'create_notice_form': create_notice_form,
                               'posted': posted,},
                              context)

Solution

You have to call save_m2m():

cnf = create_notice_form.save(commit=False)
cnf.created_by = request.user
cnf.save()
create_notice_form.save_m2m()

Excerpt from the documentation:

If your model has a many-to-many relation and you specify commit=False when you save a form, Django cannot immediately save the form data for the many-to-many relation. This is because it isn’t possible to save many-to-many data for an instance until the instance exists in the database.

To work around this problem, every time you save a form using commit=False, Django adds a save_m2m() method to your ModelForm subclass. After you’ve manually saved the instance produced by the form, you can invoke save_m2m() to save the many-to-many form data.

Answered By - catavaran