如何防止我的文件被另一个进程使用？

Question

这是here 问题的续集，我想知道为什么我的流无法涉水。

利用回答另一个问题的一些猫的想法，我现在得到了这个代码：

private readonly FileStream _fileStream;
private readonly StreamWriter _streamWriter;

. . .

private ExceptionLoggingService()
{
    const int MAX_LINES_DESIRED = 1000;
    int linesInLogFile;

    string uriPath = GetExecutionFolder() + "\\Application.log";
    string logPath = new Uri(uriPath).LocalPath;
    _fileStream = File.Open(logPath, FileMode.OpenOrCreate, FileAccess.ReadWrite);
    StreamReader _streamReader = new StreamReader(_fileStream);
    List<String> logList = new List<String>();

    while (!_streamReader.EndOfStream)
    {
        logList.Add(_streamReader.ReadLine());
    }
    linesInLogFile = logList.Count;
    while (logList.Count > MAX_LINES_DESIRED)
    {
        logList.RemoveAt(0);
    }

    if (linesInLogFile > MAX_LINES_DESIRED)
    {
        _fileStream.Close();
        File.Delete(logPath);
        File.Create(logPath);
        _fileStream.Close(); // added this; did not help
        _fileStream.Dispose(); // this also did no good
        _fileStream = File.OpenWrite(logPath); // <= exception occurs here
    }

    _streamWriter = new StreamWriter(_fileStream);

    foreach (String s in logList)
    {
        _streamWriter.WriteLine(s);
    }
    _streamWriter.Flush(); // here is okay, right (as opposed to within the foreach loop)?
}

...但是在指示的 ("OpenWrite()") 行上，我得到以下异常（我在它上面添加了两行，首先调用 Close()，然后调用 Dispose()，但异常仍然是同样）：

System.IO.IOException was unhandled
  _HResult=-2147024864
  _message=The process cannot access the file 'C:\HoldingTank\Sandbox\bin\Debug\Application.log' because it is being used by another process.

那么如果Close没有关闭_fileStream，而Dispose也没有dispose它，那该怎么办呢？

更新

这并没有严格回答我的问题，但受劳埃德评论的启发，它确实有效：

const int MAX_FILESIZE_ALLOWED = 20000;
string uriPath = GetExecutionFolder() + "\\Application.log";
string logPath = new Uri(uriPath).LocalPath;
FileInfo f = new FileInfo(logPath);
long fileLenInBytes = f.Length;
if (fileLenInBytes > MAX_FILESIZE_ALLOWED)
{
    File.Delete(logPath);
}
_fileStream = File.OpenWrite(logPath);
_streamWriter = new StreamWriter(_fileStream);

Answer 1

您可以使用FileShare 枚举之一，例如：

_fileStream = File.Open(logPath, FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.None);

您可以使用FileShare.None 锁定文件，如 MSDN 中所述：

拒绝共享当前文件。任何打开文件的请求（通过 此进程或其他进程）将失败，直到文件关闭。

但是，由于这是日志记录，我建议您使用 NLog 或 Log4Net 之类的东西，而不是自己滚动，让它处理日志输出。