EXT ComboBox - Live Search

[ch19851818]

各位大侠，我实现ComboBox - Live Search时，JSON数据都能得到，就是无法匹配，请问下是怎么回事：
JS：

var ds = new Ext.data.Store({
        proxy: new Ext.data.HttpProxy({
            url: 'test.do?reqCode=list'
        }),
        reader: new Ext.data.JsonReader({
            root: 'ROOT',
            totalProperty: 'TOTALCOUNT',
            id: 'studentname'
        }, [
            {name: 'studentname', mapping: 'studentname'}
        ])
    });
    // Custom rendering Template
    var resultTpl = new Ext.XTemplate(
    	 '<tpl for="."><div class="search-item">',
            '<h3>{studentname}</h3>',
        '</div></tpl>'
    );
    
    var search = new Ext.form.ComboBox({
        store: ds,
        minChars:2, 
        displayField:'studentname',
        typeAhead: false,
        loadingText: 'Searching...',
        width: 570,
        pageSize:10,
        hideTrigger:true,
        tpl: resultTpl,
        applyTo: 'search',
        itemSelector: 'div.search-item',
        onSelect: function(record){ // override default onSelect to do redirect
    	alert(record.data.topicId);
    	search.setValue(record.data.topicId);
       // window.location =String.format('http://extjs.com/forum/showthread.php?t={0}&p={1}', record.data.topicId, record.id);
        }
    });

JSON:

{"TOTALCOUNT":10, "ROOT":[{"rn":1,"studentcode":"xy00000002","studentname":"123456"},{"rn":2,"studentcode":"xy00000003","studentname":"66666"},

{"rn":3,"studentcode":"xy00000004","studentname":"4545"},{"rn":4,"studentcode":"xy00034753","studentname":"沈小苹"},{"rn":5,"studentcode":"xy00037999","studentname":"朱文保"},

{"rn":6,"studentcode":"xy00039017","studentname":"陈昊"},{"rn":7,"studentcode":"xy00039123","studentname":"胡凤娣"},{"rn":8,"studentcode":"xy00039163","studentname":"朱能尚"},

{"rn":9,"studentcode":"xy00039245","studentname":"王冰"},{"rn":10,"studentcode":"xy00039769","studentname":"傅王宾"}]}

[Go 旅城通票]

你的是remote加载的，每次都会从服务器下载数据，你的test.do?reqCode=list需要通过ext传递的关键字进行过滤然后返回需要的数据 如果不想每次都从服务器加载，设置store自动加载，combox的mode: 'local', var ds = new Ext.data.Store({ autoLoad: true, var search = new Ext.form.ComboBox({ store: ds, mode: 'local',