如何再次检查用户输入值 Django 模型和表单

Question

我不知道如何实际编写逻辑，但我想检查用户输入，尤其是针对产品模型（价格属性）的价格表单字段。

我已经对 django 表单进行了如下建模：

class SalesForm(forms.ModelForm):
class Meta:
    model = Sales
    fields = ['product', 'customer', 'quantity', 'price']

这是产品模型

class Product(models.Model):
name = models.CharField(max_length=100, null=True)
category = models.CharField(max_length=100, choices=CATEGORY, null=True)
cost = models.PositiveIntegerField(null=True)
price = models.PositiveIntegerField(null=True)
quantity = models.PositiveIntegerField(null=True)

这是我在views.py中逻辑上尝试做的事情

def user_add_sales(request):

sales = Sales.objects.all().order_by('-salesdate')[:5]
if request.method == 'POST':
    sales_form = SalesForm(request.POST)
    if sales_form.is_valid:
        sales_price = sales_form.cleaned_data('price')
        try:
            user_input = Product.objects.get(price = sales_price)
            sales_form.save()
            messages.success(request, 'Sales Added Successfully')
            return redirect('dashboard-user-sales')
        except user_input.DoesNotExist:
            sales_form = SalesForm()
else:
    sales_form = SalesForm()
context = {
   'sales' : sales,
   'sales_form' : sales_form,
}
return render(request, 'dashboard/user_sales.html', context)

尝试运行代码时，显示“SalesForm”对象没有“cleaned_data”属性。有人应该帮助我如何检查用户在 SalesForm 的价格字段中输入的内容是否不低于在 Product Model 中为该产品设置的价格。

Answer 1

表单通过sales_form.is_valid()方法进行验证，而不是通过属性验证，if 条件如下：

if sales_form.is_valid():
    # …
# …

在您的表单中，您可以检查给定价格是否至少是相关属性中的价格：

class SalesForm(forms.ModelForm):
    # …
    
    def clean(self, *args, **kwargs):
        data = super().clean(*args, **kwargs)
        if data['price'] < data['product'].price:
            raise ValidationError('The price of the sale is below the price of the product')
        return data