Django仅在创建视图上进行表单验证

Question

我确定这是一个简单的问题，但谷歌今天没有帮助我！ 我试图仅在Create视图阶段运行以下验证，因为在某些时候系统需要允许重复，但不是在用户创建新计算时。

forms.py

中的代码

def clean_tag_number(self):
    tag_number = self.cleaned_data['tag_number']
    try:
        Calc.objects.get(tag_number = tag_number)
    except Calc.DoesNotExist:
        return tag_number
    raise forms.ValidationError("You already have a calculation based on that tag number, please choose another.")

我已尝试在request.path中使用forms.py检查当前网址，就像我在某些模板中所做的那样，但这显然不适用于forms.py。任何指针都会非常感激。

Answer 1

您可以使用现有方法，但请先检查self.instance和self.instance.pk是否为无。

Answer 2

def clean_tag_number(self):
    tag_number = self.cleaned_data['tag_number']
    qs = self.Meta.model.objects.filter(tag_number=tag_number)
    if self.instance:
        qs = qs.exclude(pk=self.instance.id)
    if qs.count() > 0:
        raise forms.ValidationError('You already have a calculation based on that tag number, please choose another.')

    return tag_number

Answer 3

感谢帖子并详细说明Daniels的答案，我有以下工作代码。

def clean_tag_number(self):
    tag_number = self.cleaned_data['tag_number']
    if self.instance and self.instance.pk == None:
        try:
            Calc.objects.get(tag_number = tag_number)
        except Calc.DoesNotExist:
            return tag_number
        except Calc.MultipleObjectsReturned:
            raise forms.ValidationError("You already have a calculation based on that tag number, please choose another.")
        raise forms.ValidationError("You already have a calculation based on that tag number, please choose another.")
    else:
        return tag_number

这是我第一次写任何验证，所以请随时指出任何问题。