在 Django 中创建视图的行为

Question

我几乎是 Django 的新手。因为我现在想提高我的游戏水平，所以我想深入研究 基于通用 class 的视图。我已经知道如何使用模板视图，但现在我想去创建视图。

我有这些表格：

class LearningObjectiveForm(ModelForm):
  class Meta:
    exclude = ['trainee']

这些模型：

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()

创建视图：

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)

我的网址：

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'),
)

模板：

<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>

不幸的是，当我尝试提交 post 时，我收到了 Cannot assign None: "LearningObjective.trainee" does not allow null values. 错误。有人可以帮帮我吗？？我真的很困惑，不知道我应该在这里做什么：/

Answer 1

将您的 urls.py 更改为：

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'),
)

错误是你的第二个url（'^learning_objective'）拦截了对第三个url的post请求。这就是为什么你应该在正则表达式的末尾添加 $。

由于 APPEND_SLASH 设置，POST 视图也需要 / 斜杠。

在 Django 中创建视图的行为

Behaviour of Create Views in Django

django

django-models

django-forms

django-views

django-class-based-views