Обновление label после выбора в comboBox

private void Form1_Load(object sender, EventArgs e)
        {
            MySqlCommand cmd = connection.CreateCommand();
            cmd.CommandText = "SELECT concat(concat(surname,' '),concat(name,' '), patronymic) as FIO, subdivRegNumber, registration_number FROM user";
            DataTable dt2 = new DataTable();
            MySqlDataAdapter da2 = new MySqlDataAdapter(cmd);
            da2.Fill(dt2);
            comboBox1.DataSource = dt2;
            comboBox1.ValueMember = "registration_number";
            comboBox1.DisplayMember = "FIO";
            label1.Text = comboBox1.SelectedValue.ToString();
        }

    private void ComboBox1_SelectedIndexChanged(object sender, System.EventArgs e)
    {
        label1.Text = comboBox1.SelectedValue.ToString();
    }

MySqlConnection connection = new MySqlConnection("Datasource=localhost;port=3306;username=root;password=;Database=zadelkasto2;");
        private void Form1_Load(object sender, EventArgs e)
        {
            MySqlCommand cmd = connection.CreateCommand();
            cmd.CommandText = "SELECT concat(concat(surname,' '),concat(name,' '), patronymic) as FIO, subdivRegNumber, registration_number FROM user";
            DataTable dt2 = new DataTable();
            MySqlDataAdapter da2 = new MySqlDataAdapter(cmd);
            da2.Fill(dt2);
            comboBox1.DataSource = dt2;
            comboBox1.ValueMember = "registration_number";
            comboBox1.DisplayMember = "FIO";
            
        }
private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
        {
            label1.Text = comboBox1.SelectedValue.ToString();
        }