Django dependent select

Question

I know that there is a lot of answers on this question, but i am new in Django and i dont know how to implement these solutions. First what i want to do. This is my models:

class Region(models.Model):

    name = models.CharField(max_length=255, verbose_name=_("Name"))
    slug = models.SlugField(max_length=150, unique=True, null=True)

    def save(self,*args, **kwargs):
        if not self.slug:
            self.slug = slugify(self.name)
        super(Region,self).save(*args,**kwargs)

    def __unicode__(self):
        return u'%s' % (self.name)

    class Meta:
        verbose_name = _('Region')
        verbose_name_plural = _('Regions')

class District(models.Model):

    name = models.CharField(max_length=255, verbose_name=_("Name"))
    slug = models.SlugField(max_length=150, unique=True, null=True)
    region = models.ForeignKey(Region,verbose_name=_("Region"))

    def save(self, *args, **kwargs):
        if not self.slug:
            self.slug = slugify(self.name)
        super(District, self).save(*args, **kwargs)

    def is_in_region(self, region):
        if self.region == region:
            return True
        else:
            return False

    def __unicode__(self):
        return u'%s' % (self.name)

    class Meta:
        verbose_name = _("District")
        verbose_name_plural = _("Districts")

In frontend page I want to choose one region and select with districts will show districts of this region. This my views:

class SearchView(ListView):

    template_name = 'advert/list_view.html'

    def all_json_models(self, request, region):
        current_reg = Region.objects.get(slug=region)
        districts = District.objects.all().filter(region=current_reg)
        json_models = serializers.serialize("json", districts)
        return http.HttpResponse(json_models, mimetype="application/javascript")

    def get(self, request, *args, **kwargs): 
        return self.post(request, *args, **kwargs)

    def post(self, request, *args, **kwargs):
        self.request = request
        try:
            self.page = int(self.request.GET.get('page','1'))
        except:
            self.page = 1
        self.queryset = ""
        return super(SearchView, self).get(request, *args, **kwargs)

    def get_queryset(self):
        """We have to bypass the queryset because
        we are joining several object lists together. """
        return None

    def get_context_data(self, **kwargs):
        context['regions'] = Region.objects.all().order_by("name")
        return context

the get_context_data method is much longer but i write here only simple one. I use for this solution from this website http://www.devinterface.com/blog/en/2011/02/how-to-implement-two-dropdowns-dependent-on-each-other-using-django-and-jquery/ . But still select with districts is not working. I try to write method all_json_models to this class in views but still its not calling this method. Is here any one who can tell me why? Thx a lot

Answer 1

well , i coded a whole project just for you , hope this could help :) :
in this project i we have countries which have many cities
as shown in pictures, each time you select a country , only related cities shown in next combo box :)

ok , no let's see the code
(full project source code is on my github : https://github.com/nodet07/Django-Related-DropDowns)
models.py :
just 2 simple models , a country which can have many cities !

 from django.db import models
    class City(models.Model):
        name = models.CharField(max_length=50)
        country = models.ForeignKey("Country")
        def __unicode__(self):
            return u'%s' % (self.name)

    class Country(models.Model):
        name = models.CharField(max_length=50)
        def __unicode__(self):
            return u'%s' % (self.name)

views.py:

from django.shortcuts import render
from map.models import *
from django.utils import simplejson
from django.http import HttpResponse

def index(request):
    countries = Country.objects.all()
    print countries
    return render(request, 'index.html', {'countries': countries})

def getdetails(request):
    #country_name = request.POST['country_name']
    country_name = request.GET['cnt']
    print "ajax country_name ", country_name

    result_set = []
    all_cities = []
    answer = str(country_name[1:-1])
    selected_country = Country.objects.get(name=answer)
    print "selected country name ", selected_country
    all_cities = selected_country.city_set.all()
    for city in all_cities:
        print "city name", city.name
        result_set.append({'name': city.name})
    return HttpResponse(simplejson.dumps(result_set), mimetype='application/json',     content_type='application/json')

index.html :

<html>
    <head>
    <script type="text/javascript" src="http://code.jquery.com/jquery-latest.min.js"></script>
    <script type="text/javascript" src="http://yourjavascript.com/7174319415/script.js"></script>
        <script>
            $(document).ready(function(){
                 $('select#selectcountries').change(function () {
                     var optionSelected = $(this).find("option:selected");
                     var valueSelected  = optionSelected.val();
                     var country_name   = optionSelected.text();


                     data = {'cnt' : country_name };
                     ajax('/getdetails',data,function(result){

                            console.log(result);
                            $("#selectcities option").remove();
                            for (var i = result.length - 1; i >= 0; i--) {
                                $("#selectcities").append('<option>'+ result[i].name +'</option>');
                            };


                         });
                 });
            });
        </script>
    </head>

    <body>
        <select name="selectcountries" id="selectcountries">
        {% for item in countries %}
            <option val="{{ item.name }}"> {{ item.name }} </option>    
        {% endfor %}
        </select>   


        <select name ="selectcities" id="selectcities">


        </select>

    </body>
</html>