自绘进度条采用线程循环失败，自带的CprogressCtrl进度条就能？

自绘进度条Cprogress采用线程循环失败（100后又从新开始），用自带的CprogressCtrl进度条就能循环，怎么回事
/////////////// CProgressDomoDlg.h : 头文件/////////
public:
CProgress m_Progress;
//CProgressCtrl m_Progress;
afx_msg void OnBnClickedButton1();
// UINT MyThread(LPVOID pParam);
};
/////////////// CProgressDomoDlg.cpp //////////
UINT MyThread(LPVOID pParam)//这是线程
{
CCProgressDomoDlg pDlg = (CCProgressDomoDlg)pParam;
CProgress *pPro = &pDlg->m_Progress;//CProgress 自绘进度条
//CProgressCtrl *pPro = &pDlg->m_Progress;
while(1){ for (int n = 0; n<100; n++) { n++; pPro->SetPos(n); Sleep(100); }}return 0;
}
void CCProgressDomoDlg::OnBnClickedButton1()
{
AfxBeginThread(MyThread, (LPVOID)this);
}
//源码
http://download.csdn.net/detail/greless/9768091