django admin 在修改 obj 时将字段设为只读，但在添加新 obj 时需要

Question

在管理员中，我想在修改对象时禁用一个字段，但在添加新对象时使其成为必需。

django 的方法是什么？

Answer 1

对 Bernhard 和 Mario 的出色解决方案的更可插拔的解决方案，添加了对 readonly_fields 模拟的 createonly_fields 的支持：

class MyModelAdmin(admin.ModelAdmin):

    # ModelAdmin configuration as usual goes here

    createonly_fields = ['title', ]

    def get_readonly_fields(self, request, obj=None):
        readonly_fields = list(super(MyModelAdmin, self).get_readonly_fields(request, obj))
        createonly_fields = list(getattr(self, 'createonly_fields', []))
            
        if obj:  # editing an existing object
            readonly_fields.extend(createonly_fields)
        return readonly_fields

Answer 2

内联表单的情况对于 Django 2.2.x 仍然没有解决，但 solution from John 实际上非常聪明。

根据我的情况稍微调整了代码：

class NoteListInline(admin.TabularInline):
""" Notes list, readonly """
    model = Note
    verbose_name = _('Note')
    verbose_name_plural = _('Notes')
    extra = 0
    fields = ('note', 'created_at')
    readonly_fields = ('note', 'created_at')

    def has_add_permission(self, request, obj=None):
    """ Only add notes through AddInline """
    return False

class NoteAddInline(admin.StackedInline):
    """ Notes edit field """
    model = Note
    verbose_name = _('Note')
    verbose_name_plural = _('Notes')
    extra = 1
    fields = ('note',)
    can_delete = False

    def get_queryset(self, request):
        queryset = super().get_queryset(request)
        return queryset.none()  # no existing records will appear

@admin.register(MyModel)
class MyModelAdmin(admin.ModelAdmin):
    # ...
    inlines = (NoteListInline, NoteAddInline)
    # ...

Answer 3

基于 Bernhard Vallant 先前出色建议的变体，它还保留了基类提供的任何可能的自定义（如果有的话）：

class MyModelAdmin(BaseModelAdmin):

    def get_readonly_fields(self, request, obj=None):
        readonly_fields = super(MyModelAdmin, self).get_readonly_fields(request, obj)
        if obj: # editing an existing object
            return readonly_fields + ['field1', ..]
        return readonly_fields

Answer 4

如果您只想在更改视图上将所有字段设置为只读，请覆盖管理员的 get_readonly_fields：

def get_readonly_fields(self, request, obj=None):
    if obj: # editing an existing object
        # All model fields as read_only
        return self.readonly_fields + tuple([item.name for item in obj._meta.fields])
    return self.readonly_fields

并且如果您想在更改视图上隐藏保存按钮：

1. 换个角度

   def change_view(self, request, object_id, form_url='', extra_context=None):
       ''' customize edit form '''
       extra_context = extra_context or {}
       extra_context['show_save_and_continue'] = False
       extra_context['show_save'] = False
       extra_context['show_save_and_add_another'] = False # this not works if has_add_permision is True
       return super(TransferAdmin, self).change_view(request, object_id, extra_context=extra_context)
   

2. 如果用户尝试编辑，请更改权限：

   def has_add_permission(self, request, obj=None):
      # Not too much elegant but works to hide show_save_and_add_another button
       if '/change/' in str(request):
           return False
       return True
   

   此解决方案已在 Django 1.11

   上进行了测试

Answer 5

您可以覆盖管理员的get_readonly_fields 方法：

class MyModelAdmin(admin.ModelAdmin):

    def get_readonly_fields(self, request, obj=None):
        if obj: # editing an existing object
            return self.readonly_fields + ('field1', 'field2')
        return self.readonly_fields

Answer 6

仅供参考：以防其他人遇到与我遇到的相同的两个问题：

1234563 /p>

1. 这不适用于内联，因为传递给 get_readonly_fields() 的 obj 是父 obj（我有两个使用 css 或 js 的相当老套且安全性较低的解决方案）

Answer 7

遇到了类似的问题。我在 ModelAdmin 中使用“add_fieldsets”和“restricted_fieldsets”解决了这个问题。

from django.contrib import admin  
class MyAdmin(admin.ModelAdmin):
 declared_fieldsets = None
 restricted_fieldsets = (
    (None, {'fields': ('mod_obj1', 'mod_obj2')}),
    ( 'Text', {'fields': ('mod_obj3', 'mod_obj4',)}),
 )

 add_fieldsets = (
            (None, {
             'classes': ('wide',),
             'fields': ('add_obj1', 'add_obj2', )}),
             )

请参见例如：http://code.djangoproject.com/svn/django/trunk/django/contrib/auth/admin.py

但这并不能保护您的模型免受“add_objX”以后的更改。 如果你也想要这个，我认为你必须通过 Model 类的“保存”功能并检查那里的变化。

参见：www.djangoproject.com/documentation/models/save_delete_hooks/

格里兹，尼克

Answer 8

您可以通过覆盖 ModelAdmin 的 formfield_for_foreignkey 方法来做到这一点：

from django import forms
from django.contrib import admin

from yourproject.yourapp.models import YourModel

class YourModelAdmin(admin.ModelAdmin):

    class Meta:
        model = YourModel

    def formfield_for_foreignkey(self, db_field, request=None, **kwargs):
        # Name of your field here
        if db_field.name == 'add_only':
            if request:
                add_opts = (self._meta.app_label, self._meta.module_name)
                add = u'/admin/%s/%s/add/' % add_opts
                if request.META['PATH_INFO'] == add:
                    field = db_field.formfield(**kwargs)
                else:
                    kwargs['widget'] = forms.HiddenInput()
                    field = db_field.formfield(**kwargs)
            return field
        return admin.ModelAdmin(self, db_field, request, **kwargs)