Behaviour of Create Views in Django - django

Question

I am a newbie in Django pretty much. Since I want to step my game up now, I want to dive into generic class based views. I already figured out how to use template views, but now I want to go for the create views.
I have these forms:
class LearningObjectiveForm(ModelForm):
class Meta:
exclude = ['trainee']
These models:
class LearningObjective(models.Model):
trainee = models.ForeignKey(Trainee, blank = True)
learning_objective = models.TextField()
class Trainee(models.Model):
username = models.TextField()
...
class Topic(models.Model):
trainee = models.ForeignKey(Trainee, blank = True)
learning_objective = models.ManyToManyField(LearningObjective, blank = True, null = True)
topic = models.TextField()
And this create view:
class CreateLearningObjective(CreateView):
model = LearningObjective
form = LearningObjectiveForm
def form_valid(self, form):
self.object = form.save(commit=False)
if self.request.user.is_authenticated():
self.object.trainee = self.request.user
self.object.save()
return super(CreateLearningObjective, self).form_valid(form)
My urls:
from django.conf.urls import patterns, url
from programm import views
from .views import LearningObjectiveView, CreateLearningObjective
urlpatterns = patterns('',
url(r'^$', views.index, name='index'),
url(r'^learning_objective/$', LearningObjectiveView.as_view(), name = 'learning_objective'),
url(r'^learning_objective_add/$', CreateLearningObjective.as_view(), name = 'learning_objective_add'),
)
Template:
<form action="{% url 'learning_objective_add' %}" method="post">
{% csrf_token %}
<textarea name="learning_objective" rows="4"></textarea>
<p><select name="topic" size="6" multiple>
{% for lO in learning_objectives %}
{% for t in lO.topic_set.all %}
<option>{{ t.topic }}</option>
{% endfor %}
{% endfor %}
</select></p>
<input type="submit" value="Absenden"/>
</form>
unfortunately when I try to submit a post, I just receive a Cannot assign None: "LearningObjective.trainee" does not allow null values. Error. Can anybody please help me?? I am really stuck and clueless what I should do right here :/

Answer 1

Change your urls.py to:
urlpatterns = patterns('',
url(r'^$', views.index, name='index'),
url(r'^learning_objective/$', LearningObjectiveView.as_view(), name = 'learning_objective'),
url(r'^learning_objective_add/$', CreateLearningObjective.as_view(), name = 'learning_objective_add'),
)
The error is that your second url ('^learning_objective') intercepts the post request to the third url. This is why you should add $ at the end of regex.
And / slash is also required for POST views because of APPEND_SLASH setting.