自定义 Django Admin 更改表单外键以包含视图记录

Question

在 django 管理更改表单中选择外键时，我尝试添加一个 href，可以查看添加记录的加号旁边的记录。

我只是为了获取要渲染的 href 而尝试将 admins def render 复制到我自己的自定义小部件文件中，并将其添加到并对其进行子类化：

widgets.py

class RelatedFieldWidgetWrapperLink(RelatedFieldWidgetWrapper):

    def render(self, name, value, *args, **kwargs):
        rel_to = self.rel.to
        info = (rel_to._meta.app_label, rel_to._meta.object_name.lower())
        try:
            related_url = reverse('admin:%s_%s_add' % info, current_app=self.admin_site.name)
        except NoReverseMatch:
            info = (self.admin_site.root_path, rel_to._meta.app_label, rel_to._meta.object_name.lower())
            related_url = '%s%s/%s/add/' % info
        self.widget.choices = self.choices
        output = [self.widget.render(name, value, *args, **kwargs)]
        if self.can_add_related:
            # TODO: "id_" is hard-coded here. This should instead use the correct
            # API to determine the ID dynamically.
            output.append(u'<a href="%s" class="add-another" id="add_id_%s" onclick="return showAddAnotherPopup(this);"> ' % \
                (related_url, name))
            output.append(u'<img src="%simg/admin/icon_addlink.gif" width="10" height="10" alt="%s"/></a>' % (settings.ADMIN_MEDIA_PREFIX, _('Add Another')))
            output.append(u'<a href="%s" class="testing" id="add_id_%s" onclick="#"> ' % \        
                        (related_url, name))
        return mark_safe(u''.join(output))

和 admin.py

formfield_overrides = {models.ForeignKey:{'widget':RelatedFieldWidgetWrapperLink}}

但是我收到以下错误：

类型错误 init() 至少需要 4 个参数（给定 1 个）

以前有人遇到过这个问题吗？

Answer 1

RelatedFieldWidgetWrapper 小部件和您的子类不适合用作 formfield_overrides 中的小部件。 __init__ 方法具有不同的函数签名，因此会出现 TypeError。

如果您查看 django.contrib.admin.options< 中的代码/code>，可以看到在模型管理的formfield_for_dbfield方法中实例化了RelatedFieldWidgetWrapper小部件，这样它就可以传递参数 rel、admin_site 和 can_add_lated。

我认为您可能必须重写模型管理类的 formfield_for_dbfield 方法，并在那里使用自定义的 RelatedFieldWidgetWrapperLink 小部件。

class YourModelAdmin(admin.ModelAdmin):
    def formfield_for_dbfield(self, db_field, **kwargs):
        <snip>
        # ForeignKey or ManyToManyFields
        if isinstance(db_field, (models.ForeignKey, models.ManyToManyField)):
            # Combine the field kwargs with any options for formfield_overrides.
            # Make sure the passed in **kwargs override anything in
            # formfield_overrides because **kwargs is more specific, and should
            # always win.
            if db_field.__class__ in self.formfield_overrides:
                kwargs = dict(self.formfield_overrides[db_field.__class__], **kwargs)

            # Get the correct formfield.
            if isinstance(db_field, models.ForeignKey):
                formfield = self.formfield_for_foreignkey(db_field, request, **kwargs)
            elif isinstance(db_field, models.ManyToManyField):
                formfield = self.formfield_for_manytomany(db_field, request, **kwargs)

            # For non-raw_id fields, wrap the widget with a wrapper that adds
            # extra HTML -- the "add other" interface -- to the end of the
            # rendered output. formfield can be None if it came from a
            # OneToOneField with parent_link=True or a M2M intermediary.
            if formfield and db_field.name not in self.raw_id_fields:
                related_modeladmin = self.admin_site._registry.get(
                                                        db_field.rel.to)
                can_add_related = bool(related_modeladmin and
                            related_modeladmin.has_add_permission(request))
                # use your custom widget
                formfield.widget = RelatedFieldWidgetWrapperLink(
                            formfield.widget, db_field.rel, self.admin_site,
                            can_add_related=can_add_related)

            return formfield
        <snip>

其他方法

您可能会发现重写 formfield_for_foreignkey 方法比 formfield_for_dbfield 更清晰。

您可以对 Select 小部件进行子类化，并在其渲染方法中添加链接。然后，您的自定义选择小部件将由 RelatedFieldWidgetWrapper 包装。但是，我不确定您是否可以在 render 方法的范围内生成 view_url 。

from django.contrib.contenttypes.models import ContentType
from django.core.urlresolvers import reverse
from django.forms.widgets import Select

def get_admin_change_url(obj):
    ct = ContentType.objects.get_for_model(obj)
    change_url_name = 'admin:%s_%s_change' % (ct.app_label, ct.model)
    return reverse(change_url_name, args=(obj.id,))

class LinkedSelect(Select):
    def render(self, name, value, attrs=None, *args, **kwargs):
        output = super(LinkedSelect, self).render(name, value, attrs=attrs, *args, **kwargs)
        model = self.choices.field.queryset.model
        try:
            id = int(value)
            obj = model.objects.get(id=id)
            view_url = get_admin_change_url(obj)
            output += mark_safe(' <a href="%s" target="_blank">view</a> ' % (view_url,))
        except model.DoesNotExist:
            pass
        return output

class YourModelAdmin(admin.ModelAdmin):
    formfield_overrides = {models.ForeignKey:{'widget':LinkedSelect}}

Answer 2

我稍微改进了 @Alasdair 解决方案：

from django.contrib.admin.templatetags import admin_static
from django.core import urlresolvers
from django.utils import safestring
from django.utils.translation import ugettext_lazy as _

class LinkedSelect(widgets.Select):
    def render(self, name, value, attrs=None, *args, **kwargs):
        output = [super(LinkedSelect, self).render(name, value, attrs=attrs, *args, **kwargs)]

        model = self.choices.field.queryset.model
        try:
            obj = model.objects.get(id=value)
            change_url = urlresolvers.reverse('admin:%s_%s_change' % (obj._meta.app_label, obj._meta.object_name.lower()), args=(obj.pk,))
            output.append(u'<a href="%s" class="change-object" id="change_id_%s"> ' % (change_url, name))
            output.append(u'<img src="%s" width="10" height="10" alt="%s"/></a>' % (admin_static.static('admin/img/icon_changelink.gif'), _('Change Object')))
        except (model.DoesNotExist, urlresolvers.NoReverseMatch):
            pass

        return safestring.mark_safe(u''.join(output))

class YourModelAdmin(admin.ModelAdmin):
    formfield_overrides = {models.ForeignKey: {'widget': LinkedSelect}}

它使用与 RelatedFieldWidgetWrapper 相同的代码结构和样式。此外，它使用“更改”图标而不仅仅是字符串。当外键无处指向或外键指向未定义管理界面的模型时，它会优雅地生存。