如何使用表单等效实现django官方的polls示例？

Question

官方的django polls 教程很简单，但是它必须手动处理POST 异常，并且对前端进行硬编码。如何使用表格得到相同的结果？

@csrf_protect
def vote(request, question_id):
    p = get_object_or_404(Question, pk=question_id)
    if request.method == 'GET':
        return render(request, 'polls/detail.html', {
            'question': p,
        })
    if request.method == 'POST':
        try:
            selected_choice = p.choice_set.get(pk=request.POST['choice'])
        except (KeyError, Choice.DoesNotExist):
            # Redisplay the question voting form.
            return render(request, 'polls/detail.html', {
                'question': p,
                'error_message': "You didn't select a choice.",
            })
        else:
            selected_choice.votes += 1
            selected_choice.save()
            return HttpResponseRedirect(reverse('polls:results', args=(p.id,)))



#urls.py
url(r'^(?P<question_id>[0-9]+)/vote/$', views.vote, name='vote'),


#models.py
class Question(models.Model):
    question_text = models.CharField(max_length=200)
    pub_date = models.DateTimeField('date published')

    def __str__(self):
        return self.question_text

    def was_published_recently(self):
        return self.pub_date >= timezone.now() - datetime.timedelta(days=1)


class Choice(models.Model):
    question = models.ForeignKey(Question)
    choice_text = models.CharField(max_length=200)
    votes = models.IntegerField(default=0)

    def __str__(self):
        return self.choice_text



# polls/templates/polls/detail.html
<h1>{{ question.question_text }}</h1>

{% if error_message %}<p><strong>{{ error_message }}</strong></p>{% endif %}

<form action="{% url 'polls:vote' question.id %}" method="post">
{% csrf_token %}
{% for choice in question.choice_set.all %}
    <input type="radio" name="choice" id="choice{{ forloop.counter }}" value="{{ choice.id }}" />
    <label for="choice{{ forloop.counter }}">{{ choice.choice_text }}</label><br />
{% endfor %}
<input type="submit" value="Vote" />
</form>

我想通过以下方式简化流程：

if form.is_valid():
    ...
    votes += 1

和 {{ form }} 在模板中 {{ form }} 能够检测 Choice.DoesNotExist 并默认呈现任何错误消息。

Answer 1

首先你必须定义一个表单。惯例是在 forms.py 中执行此操作。表单是继承自 "forms" 的 Class。您可以使用 forms.Form，您必须自己定义表单，或者使用 forms.ModelForm，它将根据模型生成表单。

我将提供问题模型的示例以帮助您入门，但您应该阅读此内容以获取更多信息：https://docs.djangoproject.com/en/1.10/topics/forms/

哦，如果您正在寻找 "behind the scenes magic"，您可以查看基于 Class 的视图。他们为你处理很多事情。它们的定制有点复杂，但是有一些关于该主题的 youtube 教程。

forms.ModelForm 示例：

class QuestionForm(forms.ModelForm):

class Meta:
    # Define the model here: 
    model = Question
    # Define the fields that you want to show up. Alternatively you can use "exclude", in which you specify the fields that you dont want to show up.
    fields = [
            "question_text",
            "pub_date",
    ]
    # You can use labels to define custom labels.
    labels = {
            "question_text": "Question Headline",
            }

    # Specify the widgets you want to use, if they differ from the standard widgets defined by the modelField. This is especialy usefull for ForeignKeys.
    #widgets = {
    #    'question': forms.HiddenInput,
    #}

Answer 2

{##########################################}
{## pollsForm/templates/pollsForm/detail.html#}
{##########################################}
{###pay attention to {{choice_forms}}###}

<h1> {{ question.question_text }}</h1>

<form action="{% url 'pollsForm:vote' question.id %}" method="post"> {% csrf_token %}
    {{ choice_forms }}
    <input type="submit" value="Vote" />
</form>

{##########################################}
{## pollsForm/templates/pollsForm/results.html#}
{##########################################}
{#This is optional page. This is from official tutorial##}
<h1>{{ question.question_text }}</h1>

<ul>
{% for choice in question.choice_set.all %}
    <li>{{ choice.choice_text }} -- {{ choice.votes }} vote{{ choice.votes|pluralize }}</li>
{% endfor %}
</ul>

<a href="{% url 'pollsForm:vote' question.id %}">Vote again?</a>   




########################################
# pollsForm/models.py
########################################

same

########################################
# pollsForm/urls.py
########################################

from django.conf.urls import url

from . import views

# namespace='pollsForm'
# append the following line to the myproject/urls.py
#     url(r'^pollsForm/', include('pollsForm.urls', namespace='pollsForm')),

urlpatterns = [
    url(r'^(?P<question_id>[0-9]+)/vote/$', views.vote, name='vote'),
    url(r'^(?P<pk>[0-9]+)/results/$', views.ResultsView.as_view(), name='results'),
]

########################################
# pollsForm/views.py
########################################

from django.shortcuts import get_object_or_404, render
from django.http import HttpResponseRedirect
from django.core.urlresolvers import reverse
from django.views import generic
from django.views.decorators.csrf import csrf_protect
from .models import Choice, Question
from django import forms
from django.forms import widgets
from .forms import ChoiceForm

@csrf_protect
def vote(request, question_id):
    p = get_object_or_404(Question, pk=question_id)
    c_set = Choice.objects.filter(question=question_id)

    if request.method == 'GET':
        cforms = ChoiceForm()
        cforms.fields['choice_text'] = forms.ModelChoiceField(queryset=c_set,
                                                              empty_label=None,
                                                              widget=widgets.RadioSelect)
        variables = {
            'choice_forms': cforms,
            'question': p,
        }
        return render(
            request,
            'pollsForm/detail.html',
            variables,
        )

    if request.method == 'POST':
        form = ChoiceForm(request.POST)
        if form.is_valid():
            pk = form.cleaned_data['choice_text']
            selected_choice = p.choice_set.get(pk=pk)
            selected_choice.votes += 1
            selected_choice.save()
            return HttpResponseRedirect(reverse('pollsForm:results', args=(p.id,)))

        if not form.is_valid():
            # change input char to radio
            form.fields['choice_text'] = forms.ModelChoiceField(queryset=c_set,
                                                                empty_label=None,
                                                                widget=widgets.RadioSelect)
            variables = {
               'choice_forms' : form,
                'question': p,
            }
            return render(
                request,
                'pollsForm/detail.html',
                variables,
            )

# optional
class ResultsView(generic.DetailView):
    model = Question
    template_name = 'pollsForm/results.html'

这是如何将无线电表单作为后端处理的示例。

这是等同于官方民意调查应用程序的 pollsForm 应用程序，但使用表单而不是搞乱前端。它只是向前端生成 {{ choice_forms }} 。

如何使用表单等效实现django官方的polls示例？

How to implement the official django polls example equivalently by using forms?

django

django-forms

modelform