Ext.fly() 为空

function  yjczMaterial(){
qryWin526 = new Ext.Window({
title:'应急物资查询',
layout : 'fit',
width : 380,
height : 200,
closeAction : 'close',
plain : true
});
var items = new Ext.util.MixedCollection();
    qryForm526 = getQueryForm(qryWin526);
items.add("form", qryForm526);
qryWin526.items = items;
qryWin526.show();
}