c# how to store data from a text box from the first run

Question

I’m making a bakcup program in mysql database. I have a screen where or logo with server, user, password and port used in the bank.

But I don’t want to keep typing every time I run the program, so I need the program to store some data by default after the first run of it where I typed all the data.

Data I wish to store by default:

• server
• user
• door

That is, the first time I start the program, I type everything:server, user, port and password.

Already the second time I run the program, I want to have to enter only the password, without having to type everything again.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using MySql.Data.MySqlClient;
using System.IO.Ports;
using System.IO;
using System.IO.Compression;

namespace Sistema
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
        {
        }

        private void button2_Click(object sender, EventArgs e)
        {
            DialogResult dr = MessageBox.Show(" Quer fazer o backup desse banco ?\n\n" + comboBox1.Text + "\n\n Isso pode levar um tempo", "Banco selecionado!", MessageBoxButtons.YesNo);

            switch (dr)
            {
                case DialogResult.Yes:

                    string nomesever = (string)sever.Text;
                    string nomeuser = (string)user.Text;
                    string senha = (string)pass.Text;

                    if (!Directory.Exists(caminho.Text + @"\Dumps\Arquivo_SQL"))
                        Directory.CreateDirectory(caminho.Text + @"\Dumps\Arquivo_SQL");

                    if (!Directory.Exists(caminho.Text + @"\Dumps\Arquivo_ZIP"))
                        Directory.CreateDirectory(caminho.Text + @"\Dumps\Arquivo_ZIP");

                    var currentDateTime = DateTime.Now;

                    string data = DateTime.Now.ToString("dd-MM-yyyy");
                    {
                        string file = caminho.Text + @"\Dumps\Arquivo_SQL\" + comboBox1.Text + data + ".sql";//cria sql

                        using (MySqlConnection cn = new MySqlConnection())
                        {
                            cn.ConnectionString = ("server=" + nomesever + ";Port = " + porta.Text + "; pwd = " + senha + "; database = " + comboBox1.Text + "; uid=" + nomeuser + ";SslMode = none");
                            using (MySqlCommand cmd = new MySqlCommand())
                            {
                                using (MySqlBackup mb = new MySqlBackup(cmd))
                                {
                                    string fazendo = "fazendo backup";
                                    MessageBox.Show(fazendo);
                                    cmd.Connection = cn;
                                    cn.Open();
                                    mb.ExportToFile(file);
                                    cn.Close();
                                    string startPath = caminho.Text + @"\Dumps\Arquivo_SQL";
                                    string zipPath = caminho.Text + @"\Dumps\Arquivo_ZIP\" + comboBox1.Text + data + ".zip";

                                    ZipFile.CreateFromDirectory(startPath, zipPath);
                                }
                            }
                        }
                    }

                    MessageBox.Show("backup feito");
                    if (File.Exists(caminho.Text + @"\Dumps\Arquivo_SQL\" + comboBox1.Text + data + ".sql"))//exclue sql
                        File.Delete(caminho.Text + @"\Dumps\Arquivo_SQL\" + comboBox1.Text + data + ".sql");
                    break;
                case DialogResult.No:
                    break;
            }
        }

        private void Form1_Load(object sender, EventArgs e)
        {
        }

        private void textBox1_TextChanged(object sender, EventArgs e)
        {
        }

        private void button1_Click(object sender, EventArgs e)
        {
            string nomesever = (string)sever.Text;
            string nomeuser = (string)user.Text;
            string senha = (string)pass.Text;

            try
            {
                MySqlConnection cn = new MySqlConnection();
                cn.ConnectionString = ("server=" + nomesever + "; Port=" + porta.Text + " ; pwd=" + senha + "; uid=" + nomeuser + "; SslMode=none");
                cn.Open();
                MySqlCommand com = new MySqlCommand();
                com.Connection = cn;
                com.CommandText = "Show databases";
                MySqlDataReader dr = com.ExecuteReader();
                DataTable dt = new DataTable();
                dt.Load(dr);
                comboBox1.DisplayMember = "Database";
                comboBox1.DataSource = dt;
                cn.Close();

                MessageBox.Show("conectado, Selecione o banco");
            }
            catch
            {
                MessageBox.Show("Não conectado! \n verifique se os dados estão corretos.");
            }
        }

        private void clear_Click(object sender, EventArgs e)
        {
            sever.Text = "";
            user.Text = "";
            pass.Text = "";
            porta.Text = "";
            comboBox1.Text = "";
            caminho.Text = "";
        }

        private void Busca_Click(object sender, EventArgs e)
        {
            FolderBrowserDialog busca = new FolderBrowserDialog();
            busca.RootFolder = Environment.SpecialFolder.Desktop;
            busca.Description = "Selecione a pasta desejada para armazear o backup do banco de dados";
            busca.ShowNewFolderButton = false;

            if (busca.ShowDialog() == DialogResult.OK)
            {
                caminho.Text = busca.SelectedPath;
            }

            BT_Backup.Visible = true;
        }

        private void porta_TextChanged(object sender, EventArgs e)
        {
        }
    }
}

Answer 1

    StreamReader lerserver = new StreamReader (caminhot + @"\server.log");
            sever.Text = lerserver.ReadToEnd();
            lerserver.Close();

            StreamReader leruser = new StreamReader(caminhot + @"\user.log");
            user.Text = leruser.ReadToEnd();
            leruser.Close();

            StreamReader sr = new StreamReader(caminhot + @"\port.log");
            porta.Text = sr.ReadToEnd();
            sr.Close();