need help for refreshing one record of ListGrid at client

Hello!

SmartClient Version: v9.1p_2014-03-20/PowerEdition Deployment (built 2014-03-20)
GWT 2.5.1
IE-11

I want to refresh one record of listgrid at client

my code like below:

void refreshData(Record record){
//get the old data of listgrid
RecordList recordList=getDataAsRecordList();
//find the data position that need change
int pos=recordList.findIndex("RECORDTIMESTAMP",record. getAttribute("RECORDTIMESTAMP"));
//remove the data
recordList.removeAt(pos);
//add the new data
recordList.addAt(record, pos);
//refresh data
setData(recordList);
}

But it is not work.Can you help me to resolve this problem? thank you!