只允许从管理中删除模型的某些给定实例

Question

在模型的管理中，我想仅允许对某些实例执行删除操作（我的模型有一个 DateTimeField，我想禁用将此字段设置为当前月份的实例的删除操作）。

有人可以帮忙吗？

谢谢

编辑

我尝试了克里斯在下面的回答中提出的方法，但 obj 始终为 None：

class UserProfileAdmin(admin.ModelAdmin):

    def has_delete_permission(self, request, obj=None):

        # obj is always None

        return super(UserProfileAdmin, self).has_delete_permission(request, obj=obj)

Answer 1

class MyModelAdmin(admin.ModelAdmin):
     ...
     def has_delete_permission(self, request, obj=None):
         if obj is not None and \
            obj.my_date_field.month == datetime.now().month and \
            obj.my_date_field.year == datetime.now().year:

             return False

         return super(MyModelAdmin, self).has_delete_permission(request, obj=obj)

更新：

它不是“始终无”，而是在可以确定特定对象时设置为特定对象。在更改列表中，特别是在尝试从更改列表中批量删除时的场景中，它被设置为 None 因为显然无法确定单个对象。

如果您需要考虑从更改列表中删除，则必须创建自己的删除操作并替换默认的 Django 版本。类似于：

class MyModelAdmin(admin.ModelAdmin):
    ...
    actions = ['limited_delete_selected']

    # Need to remove the default delete_selected action
    def get_actions(self, request):
        actions = super(MyModelAdmin, self).get_actions(request)
        if actions.has_key('delete_selected'):
            del actions['delete_selected']
        return actions

    def limited_delete_selected(self, request, queryset):
        # filter selected items to only those that are actually deletable
        now = datetime.now()
        queryset = queryset.exclude(date_field__month=now.month, date_field__year=now.year)

        # call Django's delete_selected with limited queryset
        from django.contrib.admin.actions import delete_selected
        delete_selected(self, request, queryset)
    limited_delete_selected.short_description = "Delete selected objects or whatever you want it to say"

您实际上需要操作和原始 has_delete_permission 因为对象可以在其change_form 视图上单独删除。

Answer 2

查看有关覆盖内置模型方法的文档： https://docs.djangoproject.com/en/1.3/topics/db/models/#overriding-model-methods