为_Chtr__独立返回多个值，用于ModelChoiceField

Question

我将models.py作为：

class FoodCategory(models.Model):
    category = models.CharField(max_length = 50)
    content = models.CharField(max_length= 50, null = True,blank=True)
    preparation = models.CharField(max_length= 50, null=True, blank=True)
    time = models.CharField(max_length=50,null=True, blank=True)
    def __str__(self):
        return '%s %s %s %s' % (self.category, self.content, self.preparation, self.time)

现在我已经从django管理站点填充了FoodCategory的一些值。我需要将这些值显示为下拉字段，即类别的下拉字段，内容的另一个下拉字段以及类似的准备和时间。

我的forms.py如下：

class FoodForm(forms.ModelForm):
    category = forms.ModelChoiceField(queryset=Category.objects.all())
    time = forms.ModelChoiceField(queryset=Category.objects.all())
    preparation = forms.ModelChoiceField(queryset=Category.objects.all())
    content = forms.ModelChoiceField(queryset=Category.objects.all())
    class Meta:
        model = FoodItems
        fields = ('name','time', 'category', 'content', 'preparation', 'comment',)

但现在所有下拉字段显示为：

我需要分别将Starter-Soup，Veg，American，Breakfast分类，内容，准备和时间分开

所以我认为问题在于__str__的返回值。我怎样才能单独归还？

Answer 1

您可以通过创建自定义模型选择字段来实现此目的：

class CategoryModelChoiceField(ModelChoiceField):
    def label_from_instance(self, obj):
        return obj.category

class TimeModelChoiceField(ModelChoiceField):
    def label_from_instance(self, obj):
        return obj.time

class PreparationModelChoiceField(ModelChoiceField):
    def label_from_instance(self, obj):
        return obj.preparation

class ContentModelChoiceField(ModelChoiceField):
    def label_from_instance(self, obj):
        return obj.content

forms.py：

class FoodForm(forms.ModelForm):
    category = CategoryModelChoiceField(queryset=Category.objects.all())
    time = TimeModelChoiceField(queryset=Category.objects.all())
    preparation = PreparationModelChoiceField(queryset=Category.objects.all())
    content = ContentModelChoiceField(queryset=Category.objects.all())
    class Meta:
        model = FoodItems
        fields = ('name','time', 'category', 'content', 'preparation', 'comment',)