Django Admin - 根据当前正在编辑的对象过滤选择字段

Django Admin - Filter Choice Field based on current object being edited

我试图将正在编辑的当前对象从选择字段中排除到 select 来自同一模型的父对象。例如:

from django import forms
from django.contrib import admin

class RelationForm(forms.ModelForm):    
    parent = forms.ModelChoiceField(queryset=Ingredient.objects.exclude(id=current_ingredient_id))  

    def save(self, commit=True):
        parent = self.cleaned_data.get('parent', None)
        # ...do something with extra_field here...
        return super(RelationForm, self).save(commit=commit)

    class Meta:
        model = IngredientRelations
        exclude = ['description']

@admin.register(Ingredient)
class IngredientAdmin(admin.ModelAdmin):
    form = RelationForm

    fieldsets = (
        (None, {
             'fields': ('name', 'slug', 'description', 'parent',),
        }),
    ) 

困难在于获取正在编辑的当前对象,然后在查询集参数的 RelationForm 中获取其主键。

我曾尝试在 IngredientAdmin 中使用 ModelAdmin.formfield_for_foreignkey and ModelAdmin.formfield_for_choice_field,但没有成功。

有什么想法吗?

执行此操作的规范方法是使用当前编辑的实例 ID 更新 __init__ 方法中的 queryset

class RelationForm(forms.ModelForm):
    def __init__(self, *args, **kwargs):
        super(RelationForm, self).__init__(*args, **kwargs)
        if self.instance.id:
            self.fields['parent'].queryset = Ingredient.objects.exclude(id=self.instance.id)

    class Meta:
        model = IngredientRelations
        exclude = ['description']

最初在这个答案中看到: