django中使用json做级联选择

使用JSON代替XML做为数据传输是个不错的选择，下面我们看看django中如何使用json。

首先下载json-py的类库，http://blog.ntsky.com/wp-content/uploads/json-py-3_4.zip

我们使用关联select作为例子:

XML/HTML代码

   <select name="city_id" id="city_id" onChange="getFacilityOptions(this.value)">
{% if city_list %}
{% for city in city_list %}
<option value="{{city.id}}">{{city.name}}option>
{% endfor %}
{% endif %}
select>
<select name="facility_id" id="facility_id" style="display:none">
select>

我们选择city时候关联出facility，这里使用jquery的ajax函数

JavaScript代码

function getFacilityOptions(city_id){
    $.ajax({
        type: "GET",
        url: "/raw/facility_list/"+city_id+"/",
        dataType:   "json",
        success: function(json){
            // 显示设施
            $("#facility_id").show();

            var facilitySelect = document.getElementById("facility_id");


            // 清空
            for ( var i=facilitySelect.options.length-1; i>-1; i– ){
                facilitySelect[i] = null;
            }

            // 创建select选项
            for(i=0;i
                facilitySelect.options[i] = new Option();
                facilitySelect.options[i].text = json[i].label;
                facilitySelect.options[i].value = json[i].text;
            }
        }
    })
}

通过ajax发送请求得到json数据，然后解析json数据输出select的option

Python代码

# 城市设施列表
def facility_list(request,city_id):

    li = []

    city = get_object_or_404(City, pk=city_id)
    facility_list = CityFacility.objects.filter(city=city)
    for object in facility_list:
        d = {}
        d['label'] = object.facility.name
        d['text'] = object.facility.id

        li.append(d)

    return HttpResponse(json.write(li))

这里定义了list,里面包含了一组Dictionary

这样级联选择就OK了。选择city发送ajax请求django，django返回json数据，javascript解析json数据得到facility的select选择。