Django(part4)

1. 一个简单的form表单:
   # 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>
• forloop.counter:表示for循环执行的次数
• action="{% url ‘polls:vote‘ question.id %}":指定处理post 数据的url
• {% csrf_token % }:用于防止csrf攻击的tag,所有post的form都应该使用
2. 处理post的代码:

                       
                           #
                           polls/urls.py
   url(r‘^(?P<question_id>\d+)/vote/$‘, views.vote, name=‘vote‘),
   
   #polls/views.pyfrom django.shortcuts import get_object_or_404, render
   from django.http import HttpResponseRedirect, HttpResponse
   from django.core.urlresolvers import reverse
   
   from polls.models import Choice, Question
   # ...def vote(request, question_id):
       p = get_object_or_404(Question, pk=question_id)
       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()
           # Always return an HttpResponseRedirect after successfully dealing# with POST data. This prevents data from being posted twice if a# user hits the Back button.return HttpResponseRedirect(reverse(‘polls:results‘, args=(p.id,)))
                   

   # polls/view.py

                       
                           from  django.shortcuts import get_object_or_404, render
   
   def results(request, question_id):
       question = get_object_or_404(Question, pk=question_id)
       return render(request, ‘polls/results.html‘, {‘question‘: question})
                   

• request.POST:用于获取表单的值，同样的属性还有request.GET
• request.POST[‘choice’]:choice是key值，不存在时引发KeyError exception
• HttpResponseRedirect():参数是一个重定向的url\
• reverse():返回一个url，通过使用url name避免hardcode
3. Generic view:

                       
                           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 polls.models import Choice, Question
   
   class IndexView(generic.ListView):
       template_name = ‘polls/index.html‘
       context_object_name = ‘latest_question_list‘def get_queryset(self):
           """Return the last five published questions."""return Question.objects.order_by(‘-pub_date‘)[:5]
   
   
   class DetailView(generic.DetailView):
       model = Question
   #template_name 告诉django自动生成的template的name
   #如果不指定默认为<app name>/<model name>_detail.html
       template_name = ‘polls/detail.html‘#polls/urls.py
   #注意必须用<pk>指定匹配的组名
   urlpatterns = patterns(‘‘,
       url(r‘^$‘, views.IndexView.as_view(), name=‘index‘),
       url(r‘^(?P<pk>\d+)/$‘, views.DetailView.as_view(), name=‘detail‘),
     
   )
                   

原文：http://www.cnblogs.com/phenixyu/p/3990937.html