easyui datagrid 动态修改查询参数

tabCodeItem.datagrid({
url: "/List",
idField: 'id',
pagination: true,
pageSize: 30,
queryParams: { },
rownumbers: true,
singleSelect: true,
striped: true,
fit: true,
border: false,
...

var p = tabCodeItem.datagrid('getPager');
(p).pagination({
beforePageText: '第',//页数文本框前显示的汉字
afterPageText: '页    共 {pages} 页',
displayMsg: '共{total}条数据'

});

function srhCodeItem() {
dlgSrhCodeItem.dialog('close');
var classId = srhCodeItemClass.combobox('getValue');
var key = srhCodeItemKey.textbox('getValue');
var para = {};
if (classId != '') {
para.classId = classId;
}
if (key != '') {
para.key = key;
}

tabCodeItem.datagrid('options').queryParams = para;
tabCodeItem.datagrid('reload');
}