Django admin:仅在更改表单中排除字段

Question

如果有办法检测是否正在添加或更改模型中的信息.

如果可以,则可以使用此信息排除字段.

一些伪代码来说明我在说什么.

class SubSectionAdmin(admin.ModelAdmin):
    if something.change_or_add = 'change':
        exclude = ('field',)
    ...

谢谢

Answer 1

orwellian的答案将使整个SubSectionAdmin单例改变其排除属性.

确保在每个请求的基础上排除字段的方法是执行以下操作:

class SubSectionAdmin(admin.ModelAdmin):
    # ...
    def get_form(self, request, obj=None, **kwargs):
        """Override the get_form and extend the 'exclude' keyword arg"""
        if obj:
            kwargs.update({
                'exclude': getattr(kwargs, 'exclude', tuple()) + ('field',),
            })
        return super(SubSectionAdmin, self).get_form(request, obj, **kwargs)

这将通知表单排除那些额外的字段.

在给定的字段被排除的情况下,不确定这将如何表现...

Answer 2

class SubSectionAdmin(admin.ModelAdmin):
    # ...
    def change_view(self, request, object_id, extra_context=None):       
        self.exclude = ('field', )
        return super(SubSectionAdmin, self).change_view(request, object_id, extra_context)

Answer 3

设置self.exclude为@ steve-pike提及,使整个SubSectionAdmin单例改变其排除属性.单例是一个类,它将在每次实例化类时重用相同的实例,因此实例仅在第一次使用构造函数时创建,并且后续使用构造函数将返回相同的实例.有关更详细的描述,请参阅Wiki页面.这意味着如果您编写代码以在更改时排除字段,则意味着如果您首先添加项目,该字段将在那里,但如果您打开要更改的项目,则该字段将被排除在您的后续访问中到添加页面.

实现每个请求行为的最简单方法是使用get_fields和测试obj参数,即None如果我们要添加对象,则在我们更改对象时使用对象的实例.该get_fields方法可从Django 1.7获得.

class SubSectionAdmin(admin.ModelAdmin):
    def get_fields(self, request, obj=None):
        fields = super(SubSectionAdmin, self).get_fields(request, obj)
        if obj:  # obj will be None on the add page, and something on change pages
            fields.remove('field')
        return fields

更新:

请注意,get_fields可能会返回元组,因此您可能需要转换fields为列表以删除元素.如果您尝试删除的字段名称不在列表中,则可能还会遇到错误.因此,在某些情况下,如果您有其他排除字段的因素,最好使用列表推导构建一组排除和删除:

class SubSectionAdmin(admin.ModelAdmin):
    def get_fields(self, request, obj=None):
        fields = list(super(SubSectionAdmin, self).get_fields(request, obj))
        exclude_set = set()
        if obj:  # obj will be None on the add page, and something on change pages
            exclude_set.add('field')
        return [f for f in fields if f not in exclude_set]

或者,您也可以deepcopy在get_fieldsets方法中创建结果,在其他用例中,您可以访问更好的上下文以排除内容.最明显的是,如果您需要对字段集名称进行操作,这将非常有用.此外,如果您实际使用字段集,这是唯一的方法,因为这将省略调用get_fields.

from copy import deepcopy

class SubSectionAdmin(admin.ModelAdmin):
    def get_fieldsets(self, request, obj=None):
        """Custom override to exclude fields"""
        fieldsets = deepcopy(super(SubSectionAdmin, self).get_fieldsets(request, obj))

        # Append excludes here instead of using self.exclude.
        # When fieldsets are defined for the user admin, so self.exclude is ignored.
        exclude = ()

        if not request.user.is_superuser:
            exclude += ('accepted_error_margin_alert', 'accepted_error_margin_warning')

        # Iterate fieldsets
        for fieldset in fieldsets:
            fieldset_fields = fieldset[1]['fields']

            # Remove excluded fields from the fieldset
            for exclude_field in exclude:
                if exclude_field in fieldset_fields:
                    fieldset_fields = tuple(field for field in fieldset_fields if field != exclude_field)  # Filter
                    fieldset[1]['fields'] = fieldset_fields  # Store new tuple

        return fieldsets