如果其他用户打开应用程序，如何在txt文件中写入字符串并将其用于消息？

Question

I have a problem with write in a txt file.

My idea:

I want to load the form and create a file that is open. If the Form is close the file close, too. And in the Form_load method i create a second file with the info of the user and machinname, that I want write in the second file (user_log). If a other user start the application I want that he see a messagebox with the name of the used user of this application.

here my code:

 private void Form1_Load(object sender, EventArgs e)
        {
            try
            {
                //Globale Datei wird erzeugt 
                var stream = File.Open("log.txt", FileMode.OpenOrCreate);
                global_stream = stream;

                //Benutzername und Rechnernummer wird ermitellt
                string username = Benutzer.GetUsername();
                string machine = tarasov_lib.Computer.GetMachineName();

                // User_Log wird erstellt
                using (var user_log = File.OpenWrite("user.txt"))
                {
                    user_log.Write("Benutzername: " + username + " Rechnernummer: " + machine); //error
                }       

            }
            catch (Exception)
            {
                //Daten werden aus der User_log gelesen
                TextDatei datei = new TextDatei();
                string info = datei.ReadLine("user.txt", 0);

                MessageBox.Show(info); 
            }

        }

        private void Form1_FormClosing(object sender, FormClosingEventArgs e)
        {
            global_stream.Close(); 
        }

Answer 1

I think you can duplicate the log file into the temporary local path before load, and then read the content of the new one. Remember to close file after Read/Write immediately not on form-closing.

(Comment any idea to discuss about it)

Hope to be helpful