File.ReadLines keeps file locked after reading it and i can't write into it

Question

For some reason File.ReadLines keeps the file that im reading locked, and when i am trying to write text into it using a streamWriter, i get an error that it is being used by another process. If i don't read it first, writing into it works fine. Here is my code:

    IEnumerable<String> lines;
    private void loadCfg()
    {
        lines = File.ReadLines(Application.StartupPath + @"\server.cfg");
        foreach (var line in lines)
        {
            if (line.Contains("Port"))
            {
                portTxtBox.Text = extractValue(line);
            }
            if (line.Contains("Cars"))
            {
                maxCarsCombo.Text = extractValue(line);
            }
            if (line.Contains("MaxPlayers"))
            {
                maxPlayerCombo.Text = extractValue(line);
            }
         }
      }

   private void saveBtn_Click(object sender, EventArgs e)
    {
        StreamWriter sw = new StreamWriter(Application.StartupPath + @"\server.cfg",false);
        sw.WriteLine(lines.ElementAt(0));
        sw.Close();
    }

score 1 · Accepted Answer · answered Jun 23 '21 at 12:29

Well you should read all the lines using StreamReader class that way your file will be properly closed I altered the way you are reading lines to read all lines using StreamReader try the following version

    List<string> lines = new List<string>()
    private void loadCfg()
    {
        string temp = null;
        StreamReader rd = new StreamReader(Application.StartupPath + @"\server.cfg");
        temp = rd.ReadLine();
        while(temp != null)
        {
            lines.Add(temp);
            temp = rd.ReadLine();
        }
        rd.Close();

        foreach (var line in lines)
        {
            if (line.Contains("Port"))
            {
                portTxtBox.Text = extractValue(line);
            }
            if (line.Contains("Cars"))
            {
                maxCarsCombo.Text = extractValue(line);
            }
            if (line.Contains("MaxPlayers"))
            {
                maxPlayerCombo.Text = extractValue(line);
            }
         }
    }

   private void saveBtn_Click(object sender, EventArgs e)
    {
        StreamWriter sw = new StreamWriter(Application.StartupPath + @"\server.cfg",false);
        sw.WriteLine(lines.ElementAt(0));
        sw.Close();
    }

I have not tested the code but I am sure it will solve your problem

File.ReadLines keeps file locked after reading it and i can't write into it

1 Answers1