我不能使用FileSystemWatcher类,因为似乎坏了：有时事件“改变”触发,有时不会.它具有极低的“合并利率”.

所以我创建了一个计时器和一个FileSystemWatcher.在定时器的“tick”事件中,后台工作人员完成其工作.

问题是：如何只阅读自上次检查工作人员以来添加的行？

public LogForm()
{
    InitializeComponent();
    logWatcherTimer.Start();
}

private void logWatcherTimer_Tick(object sender,EventArgs e)
{
    FileInfo log = new FileInfo(@"C:\log.txt");
    if(!logWorker.IsBusy) logWorker.RunWorkerAsync(log);
}

private void logWorker_DoWork(object sender,DoWorkEventArgs e)
{
    // Read only new lines since last check.
    FileInfo log = (FileInfo) e.Argument;

   // Here is the main question!
}

编辑：代码解决方案(也许有一个更优雅的方式？)：

private void logWatherWorker_DoWork(object sender,DoWorkEventArgs e)
{
    // retval
    string newLines = string.Empty;
    FileInfo log = (FileInfo) e.Argument;

    // Just skip if log file hasn't changed
    if (lastLogLength == log.Length) return;

    using (StreamReader stream = new StreamReader(log.FullName))
    {
        // Set the position to the last log size and read
        // all the content added
        stream.BaseStream.Position = lastLogLength;
        newLines = stream.ReadToEnd();
    }

    // Keep track of the previuos log length
    lastLogLength = log.Length;

    // Assign the result back to the worker,to be
    // consumed by the form
    e.Result = newLines;
}