Question

我有一个保存和加载功能。当我点击“保存”时在我的表格上，我得到一个＆＃39;该过程无法访问该文件＆＃39; blah blah＆＃39;因为它正被另一个进程使用＆＃39;。

这是我的保存和加载功能代码 -

加载 -

public bool Load()
{
    string currentLine;
    string[] tokenisedLine;
    StreamReader reader;
    bool success = false; ;

    reader = new StreamReader("Appointments.txt");

    try
    {
        while ((currentLine = reader.ReadLine()) != null)
        {
            tokenisedLine = currentLine.Split(' ');

            DateTime appointmentStartTime = DateTime.Parse(tokenisedLine[0]);
            int appointmentLength = int.Parse(tokenisedLine[1]);
            string displayableDescription = tokenisedLine[2];
            string location = tokenisedLine[3];

            appointments.Add(new Appointment(appointmentStartTime, appointmentLength, displayableDescription, location));

        }
        reader.Close();
        success = true;
    }

    catch(Exception)
    {
        success = false;
    }
    return success;
}

保存 -

public bool Save()
{
    string appointStart;
    string appointLength;
    string appointDescription;
    string appointLocation;
    bool success = false;

    StreamWriter outputFile = new StreamWriter("Appointments.txt");
    try
    {   // Take appointments out of list and assign their properties to variables
        foreach (Appointment appointment in appointments)
        {
            appointStart = appointment.Start.ToString();
            appointLength = appointment.Length.ToString();
            appointDescription = appointment.DisplayableDescription;
            appointLocation = appointment.Location;

            //put variable strings on one line.
            string outputLine = appointStart + "    "+ appointLength + "    "+ appointDescription + "   " + appointLocation; ;

            // Write line to a txt file and put cursur on a new lne.
            outputFile.WriteLine(outputLine);
        }
        outputFile.Close();
        //Close the txt file and return true

        success = true;
    }
        //if unsuccessful catch the exception and return true
    catch(Exception)
    {
        success = false;
    }
    return success;
}

Answer 1

您绝对应该使用using()阻止StreamReader / StreamWriter。否则你可以随时关闭你的对象或不是错误

try{
  /*...*/
}catch(Exception){
  /*...*/
}finally{
   outputFile.Close();
}

Answer 2

如果确实没有其他进程访问该文件，很可能是因为您编写代码的方式。如果您的任何一个示例中都引发了异常，则StreamReader将不会被关闭，因此将继续访问该文件。

要解决您的问题，您可以添加finally阻止或将StreamReader放入using语句。

最后：

public bool Load()
{
    string currentLine;
    string[] tokenisedLine;
    StreamReader reader;
    bool success = false; ;

    reader = new StreamReader("Appointments.txt");

    try
    {
        while ((currentLine = reader.ReadLine()) != null)
        {
            tokenisedLine = currentLine.Split(' ');

            DateTime appointmentStartTime = DateTime.Parse(tokenisedLine[0]);
            int appointmentLength = int.Parse(tokenisedLine[1]);
            string displayableDescription = tokenisedLine[2];
            string location = tokenisedLine[3];

            appointments.Add(new Appointment(appointmentStartTime, appointmentLength, displayableDescription, location));

        }
        success = true;
    }
    catch(Exception)
    {
        success = false;
    }
    finally
    {
        reader.Close();
    }
    return success;
}

使用：

public bool Load()
{
    string currentLine;
    string[] tokenisedLine;
    bool success = false; ;

    using(var reader = new StreamReader("Appointments.txt"))
    {
        try
        {
            while ((currentLine = reader.ReadLine()) != null)
            {
                tokenisedLine = currentLine.Split(' ');

                DateTime appointmentStartTime = DateTime.Parse(tokenisedLine[0]);
                int appointmentLength = int.Parse(tokenisedLine[1]);
                string displayableDescription = tokenisedLine[2];
                string location = tokenisedLine[3];

                appointments.Add(new Appointment(appointmentStartTime, appointmentLength, displayableDescription, location));

            }
            reader.Close();
            success = true;
        }

        catch(Exception)
        {
            success = false;
        }
        return success;
    }
}

我刚刚完成Save方法，但Load方法也需要完成。

由另一个进程使用 - StreamReader / Writer

2 个答案: