bool m_run;
Void CMyDlg::OnStart()
{
      int i,j;
      CClientDC dc(this);
      while(m_run)
     {
            i = rand()%500;
            j = rand()%500;
           dc.MoveTo(i,j);
             i = rand()%500;
            j = rand()%500;
           dc.LineTo(i,j);
           Sleep(300);
     }
}void CMyDlg::OnStop()
{
     m_run = false;
}但是这样机子可能会死机,无法响应.我也试过多线程,可能是我的能力不行,请大家帮忙.....