BackgroundWorker&Timer,只读取日志文件的新行？

Question

我的应用程序写入一个日志文件(当前使用log4net).我想设置一个计时器和一个后台工作程序来读取日志文件并将其内容打印到我的表单中的某个控件中,同时它正在被写入.

我无法使用FileSystemWatcher类,因为它看起来很破碎:有时事件"已更改"会触发,有时则不会.它具有极低的"汇集率".

所以我创建了一个Timer和一个FileSystemWatcher.在计时器的"tick"事件中,后台工作人员完成其工作.

问题是:如何只读取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;
}

Answer 1

每次阅读日志时检查并存储文件大小，然后在下次阅读时在该位置启动文本阅读器（或您正在使用的任何内容）。