Question

我试图在没有创建Data.txt的情况下运行我的程序，但是每次执行时都会显示错误：“该进程无法访问文件'path'，因为它正在被另一个进程使用。” < / p>

这里是代码有错误的区域，需要明确的是，它在显示“ StreamWriter Data = new StreamWriter（“ Data.txt”）”的行上

dataCheck = @"Data.txt";
dataExists = File.Exists(dataCheck);

if (dataExists)
{
    StreamReader Data = new StreamReader(@"Data.txt");

    for (i = 0; i < 5; i++)
    {
        //takes lines from text file and stores them in an array
        activities[i] = Data.ReadLine();
    }

    for (i = 0; i < 5; i++)
    {
        try { activityTimes[i] = Int32.Parse(Data.ReadLine()); }
        catch {

            StreamWriter DataWrite = new StreamWriter("Data.txt");

            DataWrite.Write(activities[0] + "\r\n");
            DataWrite.Write(activities[1] + "\r\n");
            DataWrite.Write(activities[2] + "\r\n");
            DataWrite.Write(activities[3] + "\r\n");
            DataWrite.Write(activities[4] + "\r\n");

            DataWrite.Write(activityTimes[0] + "\r\n");
            DataWrite.Write(activityTimes[1] + "\r\n");
            DataWrite.Write(activityTimes[2] + "\r\n");
            DataWrite.Write(activityTimes[3] + "\r\n");
            DataWrite.Write(activityTimes[4] + "\r\n");

            DataWrite.Close();
    }

    }
}
else
{ 
    //creates data file with activities and times
    File.Create(dataCheck);
    StreamWriter DataWrite = new StreamWriter("Data.txt");


    DataWrite.Write(activities[0] + "\r\n");
    DataWrite.Write(activities[1] + "\r\n");
    DataWrite.Write(activities[2] + "\r\n");
    DataWrite.Write(activities[3] + "\r\n");
    DataWrite.Write(activities[4] + "\r\n");

    DataWrite.Write(activityTimes[0] + "\r\n");
    DataWrite.Write(activityTimes[1] + "\r\n");
    DataWrite.Write(activityTimes[2] + "\r\n");
    DataWrite.Write(activityTimes[3] + "\r\n");
    DataWrite.Write(activityTimes[4] + "\r\n");

    DataWrite.Close();
            }

如果有人可以解释错误/为我提供解决方案，我将不胜感激！

Answer 1

在文件不存在的情况下，您遇到的问题是调用File.Create，它将创建文件并在文件上打开流。这使您无法再在同一文件上使用StreamWriter。删除File.Create，因为它不是必需的：StreamWriter将创建文件。

其他一些技巧：StreamReader和StreamWriter都是IDisposable，因此都应放在using块中。另外，这避免了您需要调用Close的情况，该调用由隐式Dispose完成。您应该将这些using块视为打开文件的时间段，因此，由于它们正在访问文件，因此它们不必重叠。

考虑使用DataWrite.Write(activities[0] + "\r\n");而不是DataWrite.WriteLine(activities[0]);。

您已经声明了一个变量来保存文件名，因此请使用该变量，而不要在多个位置复制文件名。

有两个相同的大块代码创建文件。将其重构为方法，然后从两个地方调用该方法。

Answer 2

您正在尝试通过指定文件名来创建指向同一文件的StreamReader和StreamWriter（并在打开第二个文件之前不关闭第一个文件）。你不能那样做。例如，此代码将产生相同的结果：

public static void Main()
{
    StreamWriter sw = new StreamWriter("data.txt");
    StreamReader sr = new StreamReader("data.txt"); //: 'The process cannot access the 
                                                    // file 'data.txt' because it is being used 
                                                    // by another process.'

}

相反，您可以创建一个FileStream，然后从该StreamWriter中创建一个StreamReader和FileStream。见下文：

public static void Main()
{
    using (var fs = new FileStream("data.txt", FileMode.OpenOrCreate, FileAccess.ReadWrite))
    {
        using (var sw = new StreamWriter(fs, Encoding.ASCII, 1024, true))
        using (var sr = new StreamReader(fs, Encoding.ASCII, false, 1024, true))
        {
            sw.WriteLine("Hi");
            sw.Flush();           //Make sure everything is fully written to the file.
            fs.Position = 0;      //Go back to the beginning of the file, so we can read it.
            Console.WriteLine(sr.ReadLine()); //Hi
        }

    }
}

由于文件已在使用中，因此无法使用程序

2 个答案: