ligerGrid 取得选中行的数据

   var SelectUserIdArr = [];        
   function GetData()
        {
            var returnValue = "";
            var grid = $("#maingrid").ligerGrid();
            SelectUserIdArr.length = 0;
            var rows = grid.getSelecteds();
            if (rows.length == 0) {
                returnValue = "";
            } else {
                for (var rowid in rows) {
                    SelectUserIdArr.push(rows[rowid]["ID"]);
                }
                returnValue  = (SelectUserIdArr.join(","));
            }
            window.parent.setCallbackValue(returnValue);
            frameElement.dialog.close();
        }