Hi,
you are using getTodo.send() service to get the todo list in the datagrid,
hope i understood it right,
Then do give the command getTodo.send() immediately after
delTodo.send(delData) rather, u have a http service with id="delTodo".
In that http service put result="successHandler(event)"

private fuction successHandler(event:ResultEvent):void{

getTodo.send();
}