关于DateTimePicker

void CXXDlg::OnDatetimechangeDatetimepicker1(NMHDR* pNMHDR, LRESULT* pResult) 
{
UpdateData(); time_t t = m_Time1.GetTime();
CString str;
str.Format("%ld",t);
AfxGetApp()->WriteProfileString("ShutDown","time1",str); *pResult = 0;
}初始化为8:00:00当我在界面下调时针这个数字8时会使程序崩溃...怎么会这样?请高手指点!还有.上调就没问题.当从23:00:00调到00:00:00时也会使程序崩溃.我人也崩溃了...恳请高手指点!!