ExtJs 动态修改组件的属性值，并重新渲染组件

//定义一个组件添加到formPanel中var dqszj = { fieldLabel:'当前所在级', xtype:'combo', hiddenName:'dqszj', readOnly:true, triggerAction:'all', displayField:"dmmc", emptyText:'必填', allowBlank:false, valueField:'dmjc', store:new Ext.data.JsonStore({ url:contextPath+'/system/jcsdAction.do?method=getQtdm&dmlb=nj', autoLoad:true, fields:["dmjc","dmmc"] }) }; var form = new Ext.FormPanel({ id:'addForm', layout:'form', titile:'form', border:false, bodyStyle:'padding:5px', defaults:{ xtype:'fieldset', margins:'4 4 4 4', labelWidth:90, collapsible:true }//在此修改属性if(formData.sfbt == "true"){ textfield.allowBlank = true; textfield.emptyText = ''; textfield.reset(); textfield.hide(); textfield.show();效果如下：

//最开始尝试了很多方法，均达不到效果。

//textfield.clearInvalid();
//textfield.setEmptyText("");
//textfield.render();
//Ext.getCmp('addForm').render();


//Ext.getCmp('addForm').remove(dqszj);
//Ext.getCmp('addForm').add(dqszj);
//Ext.getCmp('addForm').doLayout();

//form.getForm().findField(xm).getEl().dom.readOnly = true;