C / C++ / MFC

void CDialogSd::OnOK() 
{
  CTime time;
  m_date.GetTime(time);
  day.Format("%d",time.GetDay());
  month.Format("%d",time.GetMonth());
  year.Format("%d",time.GetYear());
  CDialog::OnOK();
}

in the View Class:
...
  CDateTimeDlg dlg;
  CTime timeNewDateTime;

  dlg.m_DateTime = CTime::GetCurrentTime();
  if(dlg.DoModal() == IDOK)
    timeNewDateTime = dlg.m_DateTime;

======================
in the CDateTimeDlg class:
in the .h file:
...
public:
  CDateTimeDlg(CWnd *pParent = NULL);   // standard constructor
  CTime m_DateTime;
  // Dialog Data
  //{{AFX_DATA(CDateTimeDlg)
  enum { IDD = IDD_DATETIME_DLG };
  CDateTimeCtrl m_cDateTime;
  //}}AFX_DATA

in the .cpp file:
...
void CDateTimeDlg::DoDataExchange(CDataExchange* pDX)
{
  CDialog::DoDataExchange(pDX);
  //{{AFX_DATA_MAP(CDateTimeDlg)
  DDX_Control(pDX, IDC_DATETIME, m_cDateTime);
  //}}AFX_DATA_MAP
}

BEGIN_MESSAGE_MAP(CDateTimeDlg, CDialog)
  //{{AFX_MSG_MAP(CDateTimeDlg)
  ON_NOTIFY(DTN_DATETIMECHANGE, IDC_DATETIME, OnDatetimechangeDateTime)
  //}}AFX_MSG_MAP
END_MESSAGE_MAP()
...
BOOL CDateTimeDlg::OnInitDialog() 
{
  CDialog::OnInitDialog();

  m_cDateTime.SetFormat("MM/dd/yyyy HH:mm:ss");
  m_cDateTime.SetTime(&m_DateTime);
  return TRUE;  // return TRUE unless you set the focus to a control
                // EXCEPTION: OCX Property Pages should return FALSE
}

void CDateTimeDlg::OnDatetimechangeDateTime(NMHDR *pNMHDR, LRESULT *pResult) 
{
  m_cDateTime.GetTime(m_DateTime);
  *pResult = 0;
}