Django模型表单:将选择限制为group

Question

我在Django中有一个现有的模型表单。我感兴趣的领域是language_pairs模型选择字段。以下是一些条目:

  {
"model": "projects.LanguagePair",
"pk": 1,
"fields": {
  "name": "English (en) - German (de)",
  "code": "en_de"
 }
 },
 {
"model": "projects.LanguagePair",
"pk": 2,
"fields": {
  "name": "German (de) - English (en)",
  "code": "de_en"
   }
  },
  {
"model": "projects.LanguagePair",
"pk": 3,
"fields": {
  "name": "French (fr) - English (en)",
  "code": "fr_en"
}

表单代码:

class ProjectForm(forms.ModelForm):
    class Meta:
        model = Project
        fields = ('title', 'notes', 'url', 'content')
        language_pairs =   forms.ModelMultipleChoiceField(queryset=LanguagePair.objects.order_by('code'))
    def __init__(self, *args, **kwargs):
        if kwargs.get('instance'):
            initial = kwargs.setdefault('initial', {})
            initial['language_pairs'] = [t.pk for t in kwargs['instance'].language_pairs.all()]
        super(ProjectForm, self).__init__(*args, **kwargs)
    def save(self, commit=True, user=None):
        instance = super().save(commit=False)
        source_languages = set()
        if commit:
            if user:
                instance.user = user
            instance.save()
            instance.language_pairs.clear()
            for lang in self.cleaned_data['language_pairs']:
                source_languages.add(lang['code'].split("_")[0])
            if len(source_languages) !=1:
                raise ValidationError("You can only have one source language")
            for lang in self.cleaned_data['language_pairs']:
                instance.language_pairs.add(lang)
        return instance

我的问题是这是正确的地方，以提高验证错误，如果任何源语言是不同的(集有一个以上的条目)?

Answer 1

引发验证的正确位置:表单验证发生在清理数据时。如果您想定制这个过程，可以在不同的地方进行更改，每个地方都有不同的目的。去看看文件吧…

https://docs.djangoproject.com/en/1.10/ref/forms/validation/form-field-default-cleaning