关于extjs combox 从数据库获取值的问题

[xiyan_]

var ZCYH_GKCS_Store = new Ext.data.Store({
id: 'ZCYH_GKCS_Store',
proxy: new Ext.data.HttpProxy({ url: "../ServerFiles/ZDXX.ashx?Act=GetListByZDDM&Item=item_1234" }),
reader: new Ext.data.JsonReader({
totalProperty: 'results',
root: 'Rows'
}, [
{ name: 'xxdm' },
{ name: 'xxmc' }
])
});
ZCYH_GKCS_Store.load();
var ZCYH_GKCS = new Ext.form.ComboBox({
anchor: '93%',
fieldLabel: StarStr + '归口处室',
valueField: 'xxdm',
displayField: 'xxmc',
mode: 'local',
store: ZCYH_GKCS_Store,
anchor: '93%',
forceSelection: true,
emptyText: '请选择',
triggerAction: 'all',
id: 'zcyh|gkcs',
allowBlank: false
});

[xiyan_]

combox数据老是出不来.... 求大神