由另一个进程使用 - 流读取器/写入器

本文关键字：读取另一个进程 | 更新日期: 2023-09-27 17:55:15

我有一个保存和一个加载函数。当我在表单上单击"保存"时，我得到"进程无法访问文件'等等'，因为它正被另一个进程使用"。

这是我保存和加载函数的代码 -

负荷-

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;
}

救-

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;
}

由另一个进程使用 - 流读取器/写入器

你绝对应该为你的 StreamReader/StreamWriter 使用using()块。否则你总是可以关闭你的对象发生或不发生错误

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

如果确实没有其他进程访问该文件，则很可能是因为您编写代码的方式。当在任何一个示例中引发异常时，StreamReader将不会关闭，因此将继续访问该文件。

要解决您的问题，您可以添加一个finally块或将您的StreamReader放入using语句中。

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;
    }
}

我刚刚完成了Save方法，但也需要完成Load方法。