通过注册表来限定程序的使用时限

在程序初始APP的初始化中加入：
 //先获得当前的系统时间
 CTime CurTime = CTime::GetCurrentTime();
    //检查软件是否第一次运行，如果是则设定限制时间
 //我们这儿设定软件在当前时间两分分钟后禁用
 if (!IsInstalled())
 {
  CTime t = CurTime + CTimeSpan(0,0,2,0);  
  SetLimitTime(t.GetYear(),t.GetMonth(),t.GetDay(),
            t.GetHour(),t.GetMinute(),t.GetSecond());
 }
 else
 {
  //如果软件不是第一次运行，
  //则读取注册表中的时间值，与当前时间比较，
  //如果当前时间值超过了软件使用期限，则退出，否则正常启动
  CTime LimitTime;
  GetLimitTime(LimitTime);
  if (CurTime>LimitTime)
  {
   AfxMessageBox("试用版已到期，请联系购买一个正版使用",MB_OK);
   return FALSE;
  }
 } 

相关的函数如下：
BOOL IsInstalled()
{
 BOOL bInstalled = FALSE;

 DWORD dwDisposition;
 HKEY m_hKey;
 //打开注册表
 LONG ret = RegCreateKeyEx (HKEY_LOCAL_MACHINE, "SOFTWARE//TimeLimit", 0L, NULL,
  REG_OPTION_VOLATILE, KEY_ALL_ACCESS, NULL, &m_hKey, &dwDisposition);
    if (ret != ERROR_SUCCESS)    //打开注册表失败
  return FALSE;
 
 //从注册表中读入特征值
 DWORD dwVal,dwType,dwLen;
 ret = RegQueryValueEx(m_hKey, "Installed", NULL,
  &dwType,(unsigned char*)&dwVal,&dwLen);
    if (ret != ERROR_SUCCESS)      //读取数据失败
  return FALSE;                       

 //检查读到的特征值是否为1，如果是，则表明软件以前已运行过
 bInstalled = (dwVal == 1);

 //关闭注册表
 RegCloseKey(m_hKey);

 return bInstalled;
}

BOOL GetLimitTime(CTime& t)
{
 DWORD dwDisposition;
 HKEY m_hKey;
 //打开注册表
 LONG ret = RegCreateKeyEx (HKEY_LOCAL_MACHINE, "SOFTWARE//TimeLimit", 0L, NULL,
  REG_OPTION_VOLATILE, KEY_ALL_ACCESS, NULL, &m_hKey, &dwDisposition);
    if (ret != ERROR_SUCCESS)    //打开注册表失败
  return FALSE;
 
 //从注册表中读入试用期限数据
 DWORD nYear,nMonth,nDay,nHour,nMinute,nSecond;
 DWORD dwType;
 DWORD dwLen;
 ret = RegQueryValueEx (m_hKey, "Year", NULL,    //读取年份
  &dwType,(unsigned char*)&nYear,&dwLen);
    if (ret != ERROR_SUCCESS)      //读取数据失败
  return FALSE;                       
 ret = RegQueryValueEx (m_hKey, "Month", NULL,    //读取月份
  &dwType,(unsigned char*)&nMonth,&dwLen);
    if (ret != ERROR_SUCCESS)      //读取数据失败
  return FALSE;                       
 ret = RegQueryValueEx (m_hKey, "Day", NULL,    //读取天
  &dwType,(unsigned char*)&nDay,&dwLen);
    if (ret != ERROR_SUCCESS)      //读取数据失败
  return FALSE;                       
 ret = RegQueryValueEx (m_hKey, "Hour", NULL,    //读取小时
  &dwType,(unsigned char*)&nHour,&dwLen);
    if (ret != ERROR_SUCCESS)      //读取数据失败
  return FALSE;                       
 ret = RegQueryValueEx (m_hKey, "Minute", NULL,    //读取分钟
  &dwType,(unsigned char*)&nMinute,&dwLen);
    if (ret != ERROR_SUCCESS)      //读取数据失败
  return FALSE;                       
 ret = RegQueryValueEx (m_hKey, "Second", NULL,    //读取秒
  &dwType,(unsigned char*)&nSecond,&dwLen);
    if (ret != ERROR_SUCCESS)                         //读取数据失败
  return FALSE;                       
 
 //关闭注册表
 RegCloseKey(m_hKey);

 t = CTime(nYear,nMonth,nDay,nHour,nMinute,nSecond);

 return TRUE;

}

BOOL SetLimitTime(DWORD nYear,DWORD nMonth,DWORD nDay,
                DWORD nHour,DWORD nMinute,DWORD nSecond)
{
    DWORD dwDisposition;
 HKEY m_hKey;
 //打开注册表
 LONG ret = RegCreateKeyEx (HKEY_LOCAL_MACHINE, "SOFTWARE//TimeLimit", 0L, NULL,
  REG_OPTION_VOLATILE, KEY_ALL_ACCESS, NULL, &m_hKey, &dwDisposition);
    if (ret != ERROR_SUCCESS)    //打开注册表失败
  return FALSE;
 
 //向注册表中写入试用期限数据
 ret = RegSetValueEx (m_hKey, "Year", NULL,      //写入年
  REG_DWORD,(CONST BYTE*)&nYear,sizeof(DWORD));
    if (ret != ERROR_SUCCESS)                       //写入数据失败      
  return FALSE;                       
 ret = RegSetValueEx (m_hKey, "Month", NULL,     //写入月份
  REG_DWORD,(CONST BYTE*)&nMonth,sizeof(DWORD));
    if (ret != ERROR_SUCCESS)                       //写入数据失败
  return FALSE;                       
 ret = RegSetValueEx (m_hKey, "Day", NULL,       //写入天
  REG_DWORD,(CONST BYTE*)&nDay,sizeof(DWORD));
    if (ret != ERROR_SUCCESS)                       //写入数据失败
  return FALSE;                       
 ret = RegSetValueEx (m_hKey, "Hour", NULL,      //写入小时
  REG_DWORD,(CONST BYTE*)&nHour,sizeof(DWORD));
    if (ret != ERROR_SUCCESS)                       //写入数据失败
  return FALSE;                       
 ret = RegSetValueEx (m_hKey, "Minute", NULL,    //读取年份数据
  REG_DWORD,(CONST BYTE*)&nMinute,sizeof(DWORD));
    if (ret != ERROR_SUCCESS)                       //写入数据失败
  return FALSE;                       
 ret = RegSetValueEx (m_hKey, "Second", NULL,    //写入秒
  REG_DWORD,(CONST BYTE*)&nSecond,sizeof(DWORD));
    if (ret != ERROR_SUCCESS)                       //写入数据失败
  return FALSE;   
 
 //写入特征数据
 DWORD dwVal = 1;
 ret = RegSetValueEx (m_hKey, "Installed", NULL,    //写入特征值
  REG_DWORD,(CONST BYTE*)&dwVal,sizeof(DWORD));
    if (ret != ERROR_SUCCESS)    //写入数据失败
  return FALSE;                  
 //关闭注册表
 RegCloseKey(m_hKey);

 return TRUE; 
}