在 Django 1.11 admin 中创建新对象时评估只读字段

Question

假设以下模型

# models.py
class Person(models.Model):
    name = models.CharField(max_length=40)
    birthdate = models.DateField()
    age = models.CharField(max_length=3) # dont mind the type, this is just an example :)

理想的行为是在用户创建新的 Person 对象时隐藏 age 字段，并在用户提交表单时评估其值。此外，在管理员中查看对象实例时，age 字段应该可见。

为了实现这一点，我创建了一个带有自定义 ModelForm 的 ModelAdmin，如下所示

# admin.py
from django.contrib import admin
from django import forms
from .models import Person
from dateutil.relativedelta import relativedelta
import datetime

class PersonForm(forms.ModelForm):
    def clean(self):
        cleaned_data = super(PersonForm, self).clean()
        birthdate = cleaned_data.get('birthdate')
        cleaned_data['age'] = relativedelta(datetime.date.today(), birthdate).years
        return cleaned_data

class PersonAdmin(admin.ModelAdmin):
    form = PersonForm
    exclude = ('age',)

admin.site.register(Person, PersonAdmin)

但是，在提交表单后，age 字段不会被填充，可能是因为它被排除在外了。如果我删除 exclude 然后它工作，但表单显示 age 字段，这不是所需的行为。

Answer 1

您可以使用 ModelAdmin 的 save_model 方法代替自定义表单：

 class PersonAdmin(admin.ModelAdmin):

    def save_model(self, request, obj, form, change):
        birthdate = form.cleaned_data.get('birthdate')
        age = relativedelta(datetime.date.today(), birthdate).years 
        obj.age = age
        super().save_model(request, obj, form, change)

    def get_exclude(self, request, obj=None):
        if not obj:
            return ('age',)
        return self.exclude

你也可以使用 readonly_fields:

 class PersonAdmin(admin.ModelAdmin):
    readonly_fields = ('age',)

    def save_model(self, request, obj, form, change):
        birthdate = form.cleaned_data.get('birthdate')
        age = relativedelta(datetime.date.today(), birthdate).years 
        obj.age = age
        super().save_model(request, obj, form, change)

Answer 2

或者您可以隐藏表单中的输入。

# admin.py
from django.contrib import admin
from django import forms
from .models import Person
from dateutil.relativedelta import relativedelta
import datetime

class PersonForm(forms.ModelForm):
    age = forms.CharField(widget=forms.HiddenInput, required=False)
    def clean(self):
        cleaned_data = super(PersonForm, self).clean()
        birthdate = cleaned_data.get('birthdate')
        cleaned_data['age'] = relativedelta(datetime.date.today(), birthdate).years
        return cleaned_data

仅当对象为 none（创建案例）时才可以使用该表格。

class PersonAdmin(admin.ModelAdmin):
    def get_form(self, request, obj=None, **kwargs):
        if not obj:
            kwargs['form'] = PersonForm
        return super().get_form(request, obj, **kwargs)

admin.site.register(Person, PersonAdmin)

在 Django 1.11 admin 中创建新对象时评估只读字段

Evaluate a readonly field upon creating a new object in Django 1.11 admin

django

django-admin

django-modeladmin