How to split data to text boxes when read qr code data ?

private void textBox4_KeyDown(object sender, KeyEventArgs e)
        {
           
                string[] lines = textBox4.Text.Split(new string[] { Environment.NewLine }, StringSplitOptions.None);

            if (lines.Length >2)
            {
                textBox1.Text = lines[1].Substring(lines[1].IndexOf(":") + 1);
                textBox2.Text = lines[2].Substring(lines[2].IndexOf(":") + 1);
            }

Or
private void textBox4_KeyDown(object sender, KeyEventArgs e)
{
 if (textBox1.Text.Length > 0)
                    {
                        if (e.KeyCode == Keys.Return)
                        {
                            bCode = textBox4.Text;
}