EXT 省市三级联动及默认选择

var provinceStore = Ext.create('Ext.data.Store', {
                fields: ['id', 'name'],
                proxy: {
                    type: 'ajax',
                    url: '/data/CommonHandlers/ComboBoxHandler.ashx?action=province',
                    reader: {
                        type: 'json',
                        root: 'items'
                    }
                }
            });

            var cityStore = Ext.create('Ext.data.Store', {
                fields: ['id', 'name'],
                proxy: {
                    type: 'ajax',
                    url: '/data/CommonHandlers/ComboBoxHandler.ashx',
                    reader: {
                        type: 'json',
                        root: 'items'
                    }
                }
            });

            var districtStore = Ext.create('Ext.data.Store', {
                fields: ['id', 'name'],
                proxy: {
                    type: 'ajax',
                    url: '/data/CommonHandlers/ComboBoxHandler.ashx',
                    reader: {
                        type: 'json',
                        root: 'items'
                    }
                }
            });




{    
                            fieldLabel: '所属地区',
                            labelWidth: 60,
                            xtype: 'fieldcontainer',
                            combineErrors: true,
                            defaultType: 'textfield',
                            defaults: {
                                hideLabel: 'true'
                            },
                            layout: 'hbox',
                            flex: 1,
                            items: [{
                                emptyText: '请选择省份...',
                                flex: 3,
                                xtype: 'combobox',
                                name: 'Provinces',
                                id: 'Provinces',
                                hiddenName: 'name',
                                store: provinceStore,
                                selectOnFocus: true,
                                valueField: 'id',
                                displayField: 'name',
                                queryMode: 'remote',
                                editable: false,
                                listeners: {
                                    select: function (Combox, record, index) {//联动效果
                                        Ext.getCmp('Provinces_id').setValue(this.value);
                                        var city = Ext.getCmp('City');
                                        city.clearValue();
                                        city.store.removeAll();
                                        cityStore.load({
                                            params: {
                                                action: 'city', parentid: this.value
                                            }
                                        });
                                    }
                                }
                            }, {
                                emptyText: '请选择城市...',
                                flex: 3,
                                editable: false,
                                selectOnFocus: true,
                                xtype: 'combobox',
                                id: 'City',
                                name: 'City',
                                margins: '0 0 0 6',
                                valueField: 'id',
                                displayField: 'name',
                                store: cityStore,
                                queryMode: 'local',
                                listeners: {
                                    select: function (Combox, record, index) {//联动效果
                                        Ext.getCmp('City_id').setValue(this.value);
                                        var district = Ext.getCmp('District');
                                        district.clearValue();
                                        district.store.removeAll();
                                        districtStore.load({
                                            params: {
                                                action: 'city', parentid: this.value
                                            }
                                        });
                                    }
                                }
                            }, {
                                emptyText: '请选择地区...',
                                flex: 3,
                                editable: false,
                                selectOnFocus: true,
                                xtype: 'combobox',
                                id: 'District',
                                name: 'District',
                                margins: '0 0 0 6',
                                valueField: 'id',
                                displayField: 'name',
                                store: districtStore,
                                queryMode: 'local',
                                listeners: {
                                    select: function (Combox, record, index) {//联动效果
                                        Ext.getCmp('District_id').setValue(this.value);
                                    }
                                }
                            }]
                        }


                默认选择
                provinceStore.load();
                provinceStore.on("load", function () {
                    Ext.getCmp('Provinces').select(provinceStore.getAt(9));//江苏省
                }, provinceStore, true);
                cityStore.load({
                    params: {
                        action: 'city', parentid: 10
                    }
                });
                cityStore.on("load", function () {
                    Ext.getCmp('City').select(cityStore.getAt(2));//徐州市
                }, cityStore, true);
                districtStore.load({
                    params: {
                        action: 'city', parentid: 110//区县
                    }
                });