[C#] File access issue

為了確保檔案已無任何程式存取，個人使用了下列方式

檢查檔案的A C M time，確保其時間與當下時間差大於指定的秒數

public static bool CheckFileInUse(Logs logtext, string filePath, int timeout)
{
    if( !EFCS.FileExist(logtext, filePath, Conf.RUNNING_NO_CMD_MESSAGE) )
        return false;
    DateTime lastAT = System.IO.File.GetLastAccessTime(filePath);
    DateTime createT = System.IO.File.GetCreationTime(filePath);
    DateTime lastWT = System.IO.File.GetLastWriteTime(filePath);
    DateTime nowT = DateTime.Now;
    if( (nowT - lastAT).TotalSeconds < 0 ||
        (nowT - createT).TotalSeconds < 0 ||
        (nowT - lastWT).TotalSeconds < 0 )
    {
        System.IO.File.SetCreationTime(filePath, DateTime.Now);
        System.IO.File.SetLastAccessTime(filePath, DateTime.Now);
        System.IO.File.SetLastWriteTime(filePath, DateTime.Now);
    }
    lastAT = System.IO.File.GetLastAccessTime(filePath);
    createT = System.IO.File.GetCreationTime(filePath);
    lastWT = System.IO.File.GetLastWriteTime(filePath);
    nowT = DateTime.Now;
    if( (nowT - lastAT).TotalSeconds < timeout ||
        (nowT - createT).TotalSeconds < timeout ||
        (nowT - lastWT).TotalSeconds < timeout )
    {
        logtext.Out("[Info ] [" + filePath + "] creation/modification time interval < " + timeout + " secs");
        return true;
    }
    return false;
}

此外，另增加了File Lock檢查

public static bool CheckLock(Logs logtext, string _strSourceFileName)
{
    int i = 0;
    bool bResult = true;
    while( i < 20 )//Retry 20次
    {
        try
        {
            using( Stream stream = System.IO.File.Open(_strSourceFileName, FileMode.Open, FileAccess.ReadWrite, FileShare.ReadWrite) )
            {
                if( stream != null )
                {
                    logtext.Out("[Info ] [" + _strSourceFileName + "] is ready.");
                    bResult = false;
                    break;
                }
            }
        }
        catch( FileNotFoundException ex )
        {
            logtext.Out("[Info ] [" + _strSourceFileName + "] is not ready. (" + ex.Message + ")");
            bResult = true;
        }
        catch( IOException ex )
        {
            logtext.Out("[Info ] [" + _strSourceFileName + "] is not ready. (" + ex.Message + ")");
            bResult = true;
        }
        catch( UnauthorizedAccessException ex )
        {
            logtext.Out("[Info ] [" + _strSourceFileName + "] is not ready. (" + ex.Message + ")");
            bResult = true;
        }
        finally
        {
            i++;
            System.Threading.Thread.Sleep(500);
        }
    }
    return bResult;
}