//在Frame类中,增加一个成员数组,HICON m_icon[3]
//在Freame中添加,目的是对数组里的每个元素进行赋值
//setclasslong()是为了让初始的情况下,不显示MFC默认的ICON
//定义定时器,然后Frame类中,添加WM_TIMER消息映射。
m_Icon[0]= LoadIcon(AfxGetInstanceHandle(),MAKEINTRESOURCE(IDI_ICON1));
m_Icon[1]= LoadIcon(AfxGetInstanceHandle(),MAKEINTRESOURCE(IDI_ICON2));
m_Icon[2]= LoadIcon(AfxGetInstanceHandle(),MAKEINTRESOURCE(IDI_ICON3));
SetClassLong(m_hWnd,GCL_HICON,(long)m_Icon[0]);
SetTimer(1,1000,NULL);
//增加的消息处理函数
void CMainFrame::OnTimer(UINT nIDEvent)
{
static int index=1;
index = ++index%3;
SetClassLong(m_hWnd,GCL_HICON,(long)m_Icon[index]);
CFrameWnd::OnTimer(nIDEvent);
}