Extjs4.0 ComboBox如何实现三级联动_extjs

 Ext.require('Ext.*'); Ext.onReady(function(){ //定义ComboBox模型 Ext.define('State', { extend: 'Ext.data.Model', fields: [ {type: 'int', name: 'id'}, {type: 'string', name: 'cname'} ] }); //加载省数据源 var store = Ext.create('Ext.data.Store', { model: 'State', proxy: { type: 'ajax', url: 'city.asp?act=sheng&n='+new Date().getTime()+'' }, autoLoad: true, remoteSort:true }); //加载市数据源 var store1 = Ext.create('Ext.data.Store', { model: 'State', proxy: { type: 'ajax', url: 'city.asp?act=shi&n='+new Date().getTime()+'' }, autoLoad: false, remoteSort:true }); //加载区数据源 var store2 = Ext.create('Ext.data.Store', { model: 'State', proxy: { type: 'ajax', url: 'city.asp?act=qu&n='+new Date().getTime()+'' }, autoLoad: false, remoteSort:true }); Ext.create("Ext.panel.Panel",{ renderTo: document.body, width:290, height:220, title:"城市三级联动", plain: true, margin:'30 10 0 80', bodyStyle: "padding: 45px 15px 15px 15px;", defaults :{ autoScroll: true, bodyPadding: 10 }, items:[{ xtype:"combo", name:'sheng', id : 'sheng', fieldLabel:'选择省', displayField:'cname', valueField:'id', store:store, triggerAction:'all', queryMode: 'local', selectOnFocus:true, forceSelection: true, allowBlank:false, editable: true, emptyText:'请选择省', blankText : '请选择省', listeners:{ select:function(combo, record,index){ try{ //userAdd = record.data.name; var parent=Ext.getCmp('shi'); var parent1 = Ext.getCmp("qu"); parent.clearValue(); parent1.clearValue(); parent.store.load({params:{param:this.value}}); } catch(ex){ Ext.MessageBox.alert("错误","数据加载失败。"); } } } }, { xtype:"combo", name:'shi', id : 'shi', fieldLabel:'选择市', displayField:'cname', valueField:'id', store:store1, triggerAction:'all', queryMode: 'local', selectOnFocus:true, forceSelection: true, allowBlank:false, editable: true, emptyText:'请选择市', blankText : '请选择市', listeners:{ select:function(combo, record,index){ try{ //userAdd = record.data.name; var parent = Ext.getCmp("qu"); parent.clearValue(); parent.store.load({params:{param:this.value}}); } catch(ex){ Ext.MessageBox.alert("错误","数据加载失败。"); } } } }, { xtype:"combo", name:'qu', id : 'qu', fieldLabel:'选择区', displayField:'cname', valueField:'id', store:store2, triggerAction:'all', queryMode: 'local', selectOnFocus:true, forceSelection: true, allowBlank:false, editable: true, emptyText:'请选择区', blankText : '请选择区', } ] }) });