ModelChoiceField在提交表单时给出无效的选择错误 [英] ModelChoiceField gives an invalid choice error upon form submission

问题描述

我想允许用户删除与特定模型相关的外键列表。

I want to allow the user to delete a list of associated foreignkeys to a particular model.

b

class IceBox(models.Model):
    ...

class FoodItem(models.Model):
    name = models.CharField(...)
    icebox = models.ForeignKey(IceBox)

    def __unicode__(self):
        return self.name

用于选择要删除的多个食品的表单：

The form used to select multiple fooditems to be deleted:

class IceBoxEditForm(forms.Form):
        fooditems = forms.ModelChoiceField(queryset=FoodItem.objects.none(), widget=forms.CheckboxSelectMultiple(), empty_label=None)

相应的视图：

def icebox_edit(request, item=None):
        # Grab the particular icebox
        icebox = get_object_or_404(IceBox, pk=item)

        if request.method == "POST":
                form = IceBoxEditForm(request.POST)
                print request.POST
                if form.is_valid():
                        # Delete should happen
        else:
                form = IceBoxEditForm()
                # Only use the list of fooditems that this icebox holds
                form.fields['fooditems'].queryset = icebox.fooditem_set.all()

        return render_to_response('icebox_edit.html', {'form':form},context_instance=RequestContext(request))    

正确列出与该冰箱相关联的食品的复选框。但是，当我选择某些内容然后提交表单时，我会收到表单错误：

The form correctly lists checkboxes of the fooditems associated with that icebox. However, when I select something and then submit the form, I'll get the form error:

选择一个有效的选择。这个选择不是可用的选择之一。

Select a valid choice. That choice is not one of the available choices.

Django是否还有一些其他自定义验证？

Is there some other custom validation I'm missing that Django expects?

编辑：我已经尝试过这个，但是会出现语法错误：

I have tried this, but it gives a syntax error:

form:
class IceBoxEditForm(forms.Form):
        fooditems = forms.ModelChoiceField(queryset=FoodItem.objects.none(), widget=forms.CheckboxSelectMultiple(), empty_label=None)


        def __init__(self, *args, **kwargs):
              queryset = kwargs.pop('queryset', None)
              super(IceBoxEditForm, self).__init__(*args, **kwargs)

              if queryset:
                        self.fields['fooditems'].queryset = queryset

view:
        form = IceBoxEditForm(queryset=icebox.fooditem_set.all(), request.POST) # Syntax error!

        ....
    else:
        form = IceBoxEditForm(queryset=icebox.fooditem_set.all())
        ....

推荐答案

您已经更改了GET请求的字段的查询集，但不是一个帖子。因此，当您提交表单时，Django仍然使用原始的查询器，因此您的选择无效。

You've changed the queryset for the field for a GET request, but not for a POST. So when you submit the form, Django is still using the original queryset, so your selection is not valid.

在视图开始时更改它，因此发生对于POST和GET，或者更好地在窗体的 __ init __ 方法中。

Either change it at the beginning of the view, so it happens for both POST and GET, or even better do it in the form's __init__ method.

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