private void button2_Click(object sender, EventArgs e)
 {
     try
     {
         string sqlConnection = ConfigurationManager.ConnectionStrings["MaConnexion"].ConnectionString;
         mysql = new MySqlConnection(sqlConnection);
         mysql.Open();
         string       queryInsert = "insert into users(login, password, status) values ('" + textBox1.Text + "','" + textBox2.Text + "','" + comboBox1.SelectedItem + "') ";
         MySqlCommand cmd         = new MySqlCommand(queryInsert, mysql);
         cmd.ExecuteNonQuery();
         if (cmd.ExecuteNonQuery() == 0)
         {
             label4.Text = "Registrierung erfolgreich abgeschlossen !";
         }
         else
         {
             label4.Text = "Bitte alle Felder ausfüllen !";
         }
         mysql.Close();
         //this.Close();
         textBox1.Text = ""; textBox2.Text = ""; comboBox1.Text = "";
         authentification a = new authentification();
         a.Show();
     }
     catch (Exception)
     {
         MessageBox.Show("Fehler: bitte alle Felder ausfüllen ");
     }
 }
        private void signUp_Load(object sender, EventArgs e)
        {
            authentification a = new authentification();

            a.Hide();
        }