django 1.2 change_form 中编辑修改ForeignKey的值

Model如下

class People(models.Model):
    name = models.CharField(max_length = 200)
    def __unicode__(self):
        return force_unicode(self.name)

class Buy(models.Model):
    from_people = models.ForeignKey(People, related_name = 'from_people')#related_name must be 'from_people'
    to_people = models.ForeignKey(People, related_name = 'to_people')
    price = models.IntegerField()
    def __unicode__(self):
        return force_unicode(u'%s-%s-%s' % (self.from_people, self.to_people, self.price))

要实现的效果:在Buy的修改页面可以同时编辑from_people和to_people两个外键的值.
django admin页面的默认效果
需要的实现

django的帮忙文档中有通过TabularInline实现在修改People时同时修改Buy的方法,代码为

#admin.py
class BuyModelInline(djopt.TabularInline):
    model = mym.Buy
    fk_name = 'from_people'

class PeopleModelAdmin(djopt.ModelAdmin):
    list_display = ['name']
    inlines = [BuyModelInline]

效果:

查看了TabularInline的代码,发现可以实现一个从Buy到People反向外键内联类来达到目的.代码

#admin.py
from django.contrib.admin.util import flatten_fieldsets
from django.utils.functional import curry
import django.forms.models as djfmmdl
class ReverseFKTabularInline(djopt.TabularInline):
    reverse_fk_name = None
    def get_formset(self, request, obj = None, **kwargs):
        """Returns a BaseInlineFormSet class for use in admin add/change views."""
        if self.declared_fieldsets:
            fields = flatten_fieldsets(self.declared_fieldsets)
        else:
            fields = None
        if self.exclude is None:
            exclude = []
        else:
            exclude = list(self.exclude)
        exclude.extend(kwargs.get("exclude", []))
        exclude.extend(self.get_readonly_fields(request, obj))
        # if exclude is an empty list we use None, since that's the actual
        # default
        exclude = exclude or None
        defaults = {
            "form": self.form,
            "formset": self.formset,
            "fk_name": self.reverse_fk_name,
            "fields": fields,
            "exclude": exclude,
            "formfield_callback": curry(self.formfield_for_dbfield, request = request),
            "extra": self.extra,
            "max_num": self.max_num,
            "can_delete": self.can_delete,
        }
        defaults.update(kwargs)
        return self.inlineformset_factory(self.model, self.parent_model, **defaults)

    def inlineformset_factory(self, model, model_has_fk, form = djfmmdl.ModelForm,
                              formset = djfmmdl.BaseInlineFormSet, fk_name = None,
                              fields = None, exclude = None,
                              extra = 3, can_order = False, can_delete = True, max_num = None,
                              formfield_callback = lambda f: f.formfield()):
        """
        Returns an ``InlineFormSet`` for the given kwargs.
    
        You must provide ``fk_name`` if ``model`` has more than one ``ForeignKey``
        to ``model_has_fk``.
        """
        fk = djfmmdl._get_foreign_key(model, model_has_fk, fk_name = fk_name)
        # enforce a max_num=1 when the foreign key to the parent model is unique.
        if fk.unique:
            max_num = 1
        kwargs = {
            'form': form,
            'formfield_callback': formfield_callback,
            'formset': formset,
            'extra': extra,
            'can_delete': can_delete,
            'can_order': can_order,
            'fields': fields,
            'exclude': exclude,
            'max_num': max_num,
        }
        FormSet = djfmmdl.modelformset_factory(model, **kwargs)
        FormSet.fk = fk
        return FormSet

上面是基类,下面实现People内联类

#admin.py
class PeopleTabularInline(ReverseFKTabularInline):
    model = mym.People
    extra = 0
class SalerInline(PeopleTabularInline):
    reverse_fk_name = 'from_people'
    verbose_name_plural = 'Saler'
class BuyerInline(PeopleTabularInline):
    reverse_fk_name = 'to_people'
    verbose_name_plural = 'Buyer'

内联类的使用方法

#admin.py
class BuyModelAdmin(djopt.ModelAdmin):
    saler_name = make_func(mym.Buy, 'from_people__name')
    buyer_name = make_func(mym.Buy, 'to_people__name')
    list_display = [saler_name, buyer_name, 'price']
    readonly_fields = [saler_name]
    inlines = [SalerInline, BuyerInline]

完成后的效果
图中红框里的显示是readonly_fields = [saler_name]这行代码的结果