python - Django 表单 : could not convert string to float

Question

我正在尝试使用 django 表单验证表单。我有以下模型:

class Session(models.Model):
    # id = AutoField(primary_key=True) added automatically.
    sport = models.ForeignKey('Sport', unique=False, blank=False, null=False, to_field='sport', on_delete=models.CASCADE, )
    hostplayer = models.ForeignKey(User, unique=False, blank=False, null=False, on_delete=models.CASCADE, related_name='member_host', )
    guestplayer = models.ForeignKey(User, unique=False, blank=True, null=True, on_delete=models.CASCADE, related_name='member_guest', )
    date = models.DateField(blank=False, null=False, )
    time = models.TimeField(blank=False, null=False, )
    city = models.ForeignKey('City', unique=False, blank=False, null=False, to_field='city', on_delete=models.CASCADE, )
    location = models.CharField(max_length=64, unique=False, blank=False, null=False, )
    price = models.FloatField(unique=False, blank=False, null=False, default=0, )
    details = models.TextField(unique=False, blank=True, null=True, )

    def __unicode__(self):
        return unicode(self.id)

以及以下形式:

class CreateSessionForm(forms.Form):
    sport = forms.CharField()
    date = forms.DateTimeField()
    time = forms.TimeField()
    city = forms.CharField()
    location = forms.CharField()
    price = forms.FloatField(required=False, initial=0, )
    details = forms.CharField(required=False, )

    def clean_price(self):
        prc = self.cleaned_data['price']
        if prc is None:
            return 0
        return prc

有一些前端验证，但我也想使用 is_valid() 功能。我在 views.py 中有以下代码:

if request.method == "POST":
    form = CreateSessionForm(data = request.POST)

    if form.is_valid():
        # Create session object.
        session = Session.objects.create(sport=Sport.objects.get(sport = form['sport'].data), hostplayer = request.user, guestplayer = None,
                                         date = form['date'].data, time = form['time'].data, city = City.objects.get(city=form['city'].data),
>>>                                      location = form['location'].data, price = form['price'].data, details = form['details'].data)
        session.save()
        # Return to the session page if successful.
        return HttpResponseRedirect('/session/' + str(session.id) + '/')

一切正常，除了我收到的价格是''时。我想允许这一点并默认为 0。但是，我在标有 >>> 的行上收到以下错误:

could not convert string to float

调试该行时，form 中 price 的值似乎没有更新(它似乎是 '') .

当传递''时，如何将表单中的价格值更改为0？执行此操作的最佳方法是什么？

我花了 3 个小时寻找解决这个问题的方法，但没有成功。这是我第一次在 django 中使用表单，所以我很可能会遗漏一些完全明显的东西。

任何帮助将不胜感激。

Answer 1

从 form.cleaned_data 中获取值，而不是使用 form['fieldname'].data

例如:

date = form.cleaned_data['date']

请参阅 processing the data from a form 上的文档了解更多详情。