Ext Js 2中 如何获取FormPanel下items的值


var queryPanel=new Ext.FormPanel
({
//floating: true,
defaultType:'textfield',
standardSubmit: true,
method:'POST',
bodyStyle:'margin-left :30px',
//renderTo:document.body,
//renderTo:'mainUI',
frame : true,
height : 130,
//title:'用户登陆',
width:400,
closable : false,
         x:1,
         y:1,
items:[

{
id:'username',
xtype:'textfield',
fieldLabel:' 账号 ',
name:'username',
width:130,

allowBlank:true,
minLength:6,
minLengthText:'账号的长度为[6-20]',
maxLength:20,
maxLengthText:'账号的长度为[6-20]'

},
{
xtype:'textfield',
fieldLabel:' 昵称 ',
name:'nickname',
width:130,
allowBlank:true,

}
],我想在下面调用items下 name:'username', 这个的值 应该怎么写呢？？跪求