Django管理员内联的国家/州/城市下拉菜单

Question

我有一个BusinessBranch模型的城市外键.我的城市模型还有州和县模型的州和国家外键.我很难在BusinessBranchInline中显示State和Country下拉菜单.实现这一目标的最佳方法是什么？如果下拉菜单根据其父级的值过滤项目,那将是很好的.

django admin screenshot http://i33.tinypic.com/15n69mq.png

Answer 1

有点hackery,这是非常可行的.

在以下示例中,使用County而不是State和Municipality而不是City.所以,模型如下:

class County(models.Model):
    name = models.CharField(_('Name'), max_length=100, unique=True)

class Municipality(models.Model):
    county = models.ForeignKey(County, verbose_name=_('County'))
    name = models.CharField(_('Name'), max_length=100)

class Location(models.Model):
    name = models.CharField(max_length=100)
    county = models.ForeignKey(County, verbose_name=_('County'))
    municipality = models.ForeignKey(Municipality,
            verbose_name=_("Municipality"))

问题有两个方面:客户端JavaScript和服务器端字段呈现.

客户端JavaScript(使用JQuery,假设从/site_media/js/municipality.js提供)如下:

var response_cache = {};

function fill_municipalities(county_id) {
  if (response_cache[county_id]) {
    $("#id_municipality").html(response_cache[county_id]);
  } else {
    $.getJSON("/municipalities_for_county/", {county_id: county_id},
      function(ret, textStatus) {
        var options = '<option value="" selected="selected">---------</option>';
        for (var i in ret) {
          options += '<option value="' + ret[i].id + '">'
            + ret[i].name + '</option>';
        }
        response_cache[county_id] = options;
        $("#id_municipality").html(options);
      });
  }
}

$(document).ready(function() {
  $("#id_county").change(function() { fill_municipalities($(this).val()); });
});

现在,您需要Ajax视图来服务属于给定县的市政当局(假设从/ citiesities_for_county /服务):

from django.http import JSONResponse
from django.utils.encoding import smart_unicode
from django.utils import simplejson

from myproject.places.models import Municipality

def municipalities_for_county(request):
    if request.is_ajax() and request.GET and 'county_id' in request.GET:
        objs = Municipality.objects.filter(county=request.GET['county_id'])
        return JSONResponse([{'id': o.id, 'name': smart_unicode(o)}
            for o in objs])
    else:
        return JSONResponse({'error': 'Not Ajax or no GET'})

最后,admin.py中用于呈现字段的服务器端代码如下所示.一,进口:

from django import forms
from django.forms import widgets
from django.forms.util import flatatt
from django.utils.encoding import smart_unicode
from django.utils.safestring import mark_safe
from django.contrib import admin
from django.utils.translation import ugettext_lazy

from myproject.places.models import Municipality, Location

然后,小部件:

class MunicipalityChoiceWidget(widgets.Select):
    def render(self, name, value, attrs=None, choices=()):
        self.choices = [(u"", u"---------")]
        if value is None:
            # if no municipality has been previously selected,
            # render either an empty list or, if a county has
            # been selected, render its municipalities
            value = ''
            model_obj = self.form_instance.instance
            if model_obj and model_obj.county:
                for m in model_obj.county.municipality_set.all():
                    self.choices.append((m.id, smart_unicode(m)))
        else:
            # if a municipality X has been selected,
            # render only these municipalities, that belong
            # to X's county
            obj = Municipality.objects.get(id=value)
            for m in Municipality.objects.filter(county=obj.county):
                self.choices.append((m.id, smart_unicode(m)))

        # copy-paste from widgets.Select.render
        final_attrs = self.build_attrs(attrs, name=name)
        output = [u'<select%s>' % flatatt(final_attrs)]
        options = self.render_options(choices, [value])
        if options:
            output.append(options)
        output.append('</select>')
        return mark_safe(u'\n'.join(output))

接下来,表格:

class LocationForm(forms.ModelForm):
    municipality = forms.ModelChoiceField(Municipality.objects,
            widget=MunicipalityChoiceWidget(),
            label=ugettext_lazy("Municipality"), required=False)

    class Meta:
        model = Location

    def __init__(self, *args, **kwargs):
        """
        We need access to the county field in the municipality widget, so we
        have to associate the form instance with the widget.
        """
        super(LocationForm, self).__init__(*args, **kwargs)
        self.fields['municipality'].widget.form_instance = self

最后,管理类:

class LocationAdmin(admin.ModelAdmin):
    form = LocationForm
    class Media:
        js = ('http://ajax.googleapis.com/ajax/libs/jquery/1.4.0/jquery.min.js',
                '/site_media/js/municipality.js')

admin.site.register(Location, LocationAdmin)

如果有些事情仍然不清楚,请告诉我.