该进程无法访问该文件，因为它正被另一个进程使用。 （文本文件不会关闭）

Question

在此代码块检查最后一次重新启动 PC 之后，我正在尝试写入文本文件。下面的代码从文本文件中读取，即最后一次重新启动 PC，并从那里确定是否显示启动画面。但是，在此方法运行后，我需要将当前的“系统正常运行时间”写入文本文件。但我不断收到一个错误，说文本文件正在使用中。这让我发疯了。我已确保所有 StreamWriters 和 StreamReaders 都已关闭。我试过使用语句。我试过 GC.Collect。我觉得我已经尝试了一切。

任何帮助将不胜感激。

    private void checkLastResart()
    {
        StreamReader sr = new StreamReader(Path.GetDirectoryName(Application.ExecutablePath) + @"\Settings.txt");
        if (sr.ReadLine() == null)
        {
            sr.Close();
            MessageBox.Show("There was an error loading 'System UpTime'. All settings have been restored to default.");
            StreamWriter sw = new StreamWriter(Path.GetDirectoryName(Application.ExecutablePath) + @"\Settings.txt", false);
            sw.WriteLine("Conversion Complete Checkbox: 0");
            sw.WriteLine("Default Tool: 0");
            sw.WriteLine("TimeSinceResart: 0");
            sw.Flush();
            sw.Close();
        }
        else
        {
            try
            {
                StreamReader sr2 = new StreamReader(Path.GetDirectoryName(Application.ExecutablePath) + @"\Settings.txt");
                while (!sr2.EndOfStream)
                {
                    string strSetting = sr2.ReadLine();
                    if (strSetting.Contains("TimeSinceResart:"))
                    {
                        double lastTimeRecorded = double.Parse(strSetting.Substring(17));

                        //If the lastTimeRecorded is greater than timeSinceResart (computer has been resarted) OR 2 hours have passed since LVT was last run
                        if (lastTimeRecorded > timeSinceRestart || lastTimeRecorded + 7200 < timeSinceRestart)
                        {
                            runSplashScreen = true;
                        }
                        else
                        {
                            runSplashScreen = false;
                        }
                    }
                }
                sr2.Close();
                sr2.Dispose();
            }
            catch (Exception e) { MessageBox.Show("An error has occured loading 'System UpTime'.\r\n\r\n" + e); }
        }
    }               

以下是运行上述代码后写入文本文件的示例。无论我打开 StreamWriter 还是使用 File.WriteAllLines，都会立即抛出错误。

StreamWriter sw = new StreamWriter(Path.GetDirectoryName(Application.ExecutablePath) + @"\Settings.txt");
            string[] lines = File.ReadAllLines(Path.GetDirectoryName(Application.ExecutablePath) + @"\Settings.txt");
            lines[2] = "TimeSinceResart: " + timeSinceRestart;
            foreach (string s in lines)
                sw.WriteLine(s);

Answer 1

你的写代码应该这样改

string file = Path.Combine(Path.GetDirectoryName(Application.ExecutablePath),"Settings.txt");

// First read the two lines in memory
string[] lines = File.ReadAllLines(file);

// then use the StreamWriter that locks the file
using(StreamWriter sw = new StreamWriter(file))
{
     lines[2] = "TimeSinceResart: " + timeSinceRestart;
     foreach (string s in lines)
         sw.WriteLine(s);
}

这样，StreamWriter 上的锁不会阻塞 FileReadAllLines 的读取。
说了这么多，请注意几点。不要使用字符串连接创建路径字符串，使用 Path 类的静态方法。但最重要的是，当您创建像流这样的一次性对象时，请务必使用using statement 正确关闭文件

完成回答您的评论。代码的第一部分也使用 using 语句

private void checkLastResart()
{
    string file = Path.Combine(Path.GetDirectoryName(Application.ExecutablePath),"Settings.txt");
    using(StreamReader sr = new StreamReader(file))
    {
        if (sr.ReadLine() == null)
        {
            sr.Close();
            MessageBox.Show(...)
            using(StreamWriter sw = new StreamWriter(file, false))
            {
                sw.WriteLine("Conversion Complete Checkbox: 0");
                sw.WriteLine("Default Tool: 0");
                sw.WriteLine("TimeSinceResart: 0");
                sw.Flush();
            }
        }
        else
        {
            ....
        }
    } // exit using block closes and disposes the stream
}

Answer 2

在您创建sr2 的位置，sr 仍然打开 settings.txt。