如何在用户投票后将投票改为投票？

Question

这条代码运行得很好。我唯一想要更改的是在用户投票后将“表决”按钮提交为“投票”，而不是显示“您已经投票”的错误消息.So，用户在下次登录投票时可以知道他已经投票了哪些选项。

urls.py

   path('<slug>/',views.options,name='options'),
   path('<slug>/vote/', views.vote, name='vote'),

models.py

 class Category(models.Model):
    name = models.CharField(max_length=250)
    slug = AutoSlugField(populate_from='name')
    details = models.TextField(blank=True)
    image = models.ImageField(blank=True,upload_to='categories')
    views = models.IntegerField(default=0)
    created = models.DateTimeField(auto_now=True)
    modified = models.DateTimeField(auto_now_add=True)
    active = models.BooleanField(default=True)

    def __str__(self):
        return self.name

    class Meta:
        verbose_name_plural = "Categories"


class Option(models.Model):
    name = models.CharField(max_length=250)
    slug = AutoSlugField(populate_from='name')
    image = models.ImageField(blank=True,upload_to='options')
    details = models.TextField()
    category = models.ForeignKey(Category, on_delete=CASCADE)
    votes = models.IntegerField(default=0)
    active = models.BooleanField(default=True)

    def __str__(self):
        return self.name


class Vote(models.Model):
    option = models.ForeignKey(Option, on_delete=CASCADE)
    voter = models.ForeignKey(User, on_delete=CASCADE)
    slug = AutoSlugField(populate_from='option')

    def __str__(self):
        return self.voter

views.py

def options(request,slug):
category = Category.objects.get(slug=slug)
category.views += 1
category.save()
options = category.option_set.all().order_by('-votes')
if request.method == "POST":
    if request.user.is_authenticated:
        form = CommentForm(request.POST)
        if form.is_valid():
            comment = form.save(commit=False)
            comment.category = category
            comment.user = request.user
            comment.save()
            messages.success(request, 'Comment Posted.')
    else:
        messages.error(request, 'You have to login first to give comment')
        return redirect('rank:login')
else:
    form = CommentForm()
return render(request, 'rank/options.html', {'options': options,'form':form,'title': 'options','category':category})

def vote(request,slug):
if request.user.is_authenticated:
    option = Option.objects.get(slug=slug)
    category = option.category

    if Vote.objects.filter(slug=slug,voter_id=request.user.id).exists():
         messages.error(request,'You Already Voted!')
         return redirect('rank:options', category.slug)
    else:
        option.votes += 1
        option.save()
        voter = Vote(voter=request.user,option=option)
        voter.save()
        messages.success(request,'Voted.{} peoples also agree with you.'.format(option.votes-1))
        return redirect('rank:options',category.slug)
else:
    messages.error(request,"You have to login first to vote.")
    return redirect('rank:login')

options.html

<ol type="1">
          <center>{% bootstrap_messages %}</center>
    {% for option in options %}

     <div class="col-lg-6 col-md-6 mb-6">
              <div class="card h-100">
                <div class="card-body">
                    <b><li>
                  <img src="/media/{{option.image}}" width="400" height="300">
                 <h4>{{option.name}}
                  </h4>
                  <h5 class="card-text">{{ option.details}}</h5>
                      <h5>{{ option.votes }} votes</h5>
                       <form action="{% url 'rank:vote' option.slug %}" method="post">
                           {% csrf_token %}
                <input type="submit" class="btn btn-success" value="Vote" >
                       </form>
                         </li></b>
                </div>
                <div class="card-footer">
                  <small class="text-muted"></small>
                </div>


              </div>
                </div>
         {% empty %}
    <div class="card w-100">
    <div class="card-body">
        <h4>Item not available</h4>
    </div>
    </div>

    {% endfor %}
     </ol>

Answer 1

实现这一目标的最简单方法可能是向每个选项添加一个属性，以指示当前登录的用户在将选项传递给模板之前是否对该选项进行了投票。

例如：

def options(request,slug):
    category = Category.objects.get(slug=slug)
    category.views += 1
    category.save()
    options = category.option_set.all().order_by('-votes')

    # Indicate whether the user has voted or not
    for option in options:
        option.has_voted = option.vote_set.filter(voter=request.user).exists()

    ...

    return render(request, 'rank/options.html', {'options': options,'form':form,'title': 'options','category':category})

然后，在呈现按钮时，可以检查模板中的has_voted属性：

{% if option.has_voted %}
    You already voted
{% else %}
    <input type="submit" class="btn btn-success" value="Vote" >
{% endif %}