Django基础，Day5 - form表单投票详解

投票URL

polls/urls.py：

1 2	# ex: /polls/5/vote/  url(r'^(?P<question_id>[0-9]+)/vote/$', views.vote, name='vote'),

创建投票form表单

polls/templates/polls/detail.html：

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<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>

代码解释：

 {{ forloop.counter }} : for 循环次数

{% csrf_token %} : 解决POST请求跨域问题 Cross Site Request Forgeries

{% if  %}  {% endif %}:判断

{% for  %} {% endfor %}:循环

投票Views 逻辑处理

投票 views vote in polls/views.py：

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from django.http import HttpResponse, HttpResponseRedirect from django.urls import reverse   def vote(request, question_id):     question = get_object_or_404(Question, pk=question_id)     try:         selected_choice = question.choice_set.get(pk=request.POST['choice'])     except (KeyError, Choice.DoesNotExist):         # Redisplay the question voting form.         return render(request, 'polls/detail.html', {             'question': question,             '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=(question.id,)))

代码解释：

request.POST,request.GET： 分别可获得POST或GET方法的参数值，如上 request.POST['choice'] 可取得POST请求中，name值为choice的Value值。若POST参数中没有choice，则会产生KeyError。

HttpResponseRedirect：重定向跳转，提交成功后进行自动重定向跳转是web 开发的一个良好实践。防止数据提交两次。

投票结果页 Views 逻辑处理

views results in polls/views.py:

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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})

投票结果显示 template

polls/templates/polls/results.html：

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<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 'polls:detail' question.id %}">Vote again?</a>

实现结果

1、访问detail.html：http://localhost:8000/polls/1/

2、选择后，点击vote投票，跳转到结果页 results.html