UpdatePanel'UpdatePanel1'中的触发器找不到ID为'GridView1'的控件

I have two gridview in update panel and m adding entries from one gridview to another on selectedIndexChanged event what m trying to do is updating update panel on this event selectedindexchanged ...but my gridview is inside accordian control so it does not get initialized and hence i get this error .....I have two gridview in update panel and m addin