Ext的combox设置成只读的问题

Ext的combox设置成只读的，让别人不能下拉？但是要显示，如果加上disable：true的话，又无法把值传到后台？本人用的Ext版本是3.0的，下面是代码
var form1_id = new Ext.form.ComboBox({
id: 'form1_id',
name: 'id',
hiddenName: 'id',
fieldLabel: '*所属区域',
editable : false,

typeAhead: true,
lazyRender: true,
readOnly:true,

    mode: 'remote',
    store: new Ext.data.Store({
        proxy: new Ext.data.HttpProxy({
            url: '<c:url value="。。。。.do" />?action=id_load'
        }),
        reader: new Ext.data.JsonReader({
                root: 'data',
                id: 'id'
            }, 
            ['id', 'Name']
        )
    }),
     valueField: 'id',
    displayField: 'Name'

});

怎么设置让显示出来后别人只能看，而无法操作，同时值要传到后台？这里设置的 readOnly:true没用

    <script type="text/javascript">

Ext.onReady(function(){
var data = {"items":[{"name":"yyf123","password":"123","userId":1},{"name":"yyf345","password":"456","userId":2}],"result":2} ;

var store = new Ext.data.JsonStore({
        autoLoad:true, 
        fields:[{name:'name',type:'String'},   
                {name:'password',type:'String'},   
                {name:'userId',type:'int'}   
        ], 
        root:'items',
        data: data
});

myComboBox = Ext.extend(Ext.form.ComboBox, {
store: store,
emptyText: '请选择',
mode: 'local',
triggerAction: 'all',
maxHeight:80,
valueField: 'userId',
displayField: 'name',
lastQuery:"",
notShow:false, //加一个属性 默认为FALSE
renderTo: 'combo',
initComponent : function(config){
Ext.apply(this,config)
Ext.form.ComboBox.superclass.initComponent.call(this);
},
onTriggerClick : function(){
//如果if为真 则直接return 下拉不出来
if( this.readOnly || this.disabled || this.notShow){
return;
}
if(this.isExpanded()){
this.collapse();
this.el.focus();
}else {
this.onFocus({});
if(this.triggerAction == 'all') {
this.doQuery(this.allQuery, true);
} else {
this.doQuery(this.getRawValue());
}
this.el.focus();
}
},
HideCombo:function(b){ //加一个函数
this.notShow = b;
}

})
var combo = new myComboBox();

Ext.get("show").on("click",function(){
            combo.HideCombo(false)


})

Ext.get("readOnly").on("click",function(){
    combo.HideCombo(true)
    combo.setEditable(false)
})

});

    <input type="button" id="show" value="能下拉">


    <input type="button" id="readOnly" value="不能下拉">


</body>

[code="java"]
var store = new Ext.data.SimpleStore({

fields: ['abbr', 'state'],

data : Ext.exampledata.res_type // from states.js//获得数据

});

var combo = new Ext.form.ComboBox({

store: store,

displayField:'state',

typeAhead: true,

mode: 'local',

triggerAction: 'all',

emptyText:'选择物品类型',

//selectOnFocus:true,

//forceSelection:true,

disable:true

//resizable:true

});

combo.applyTo('resType');

[/code]

...
readOnly : true,
hideTrigger : true,
...

设置一个hiddenField

就是再写一个用于传值的隐藏域