用线程池时遇到的问题        
        private void pbWhiteBoard_MouseMove(object sender, MouseEventArgs e)
        {
            if (MouseButtons == MouseButtons.Left)
            {
                edit_PaintMsg.DrawAction = ExWhiteBoard.DrawAction.EXE;
                edit_PaintMsg.DrawPoint = new Point(e.X, e.Y);   //这里PaintMsg 是自定义的结构
                ThreadPool.QueueUserWorkItem(new WaitCallback(SendPaintMsg), edit_PaintMsg);
            }
        }
        private void SendPaintMsg(object stateInfo)  //这个如果是做为值传过去了,那就不用担心同步问题,
                                   //因为在线程里已经备份了值,前面edit_PaintMsg怎么改无所谓
                                   //关键时这个object 传的是值还是引用?还是不能传?不能传怎么办?
        {
            string msg = stateInfo.ToString();
          。