这里主要用到了一个函数：
BOOL SetWindowPos( const CWnd* pWndInsertAfter, int x, int y, int cx, int cy, UINT nFlags);
具体用法可以参看MSDN
void CSYSLoaderDlg::OnCheckFront()
{
// TODO: Add your control notification handler code here
if (m_checked == TRUE)
{
m_checked = FALSE;
SetWindowPos(&CWnd::wndNoTopMost,0,0,0,0,SWP_NOMOVE|SWP_NOSIZE);
}
else
{
m_checked = TRUE;
SetWindowPos(&CWnd::wndTopMost,0,0,0,0,SWP_NOMOVE|SWP_NOSIZE);
}
}