private void button1_Click(object sender, EventArgs e) { if (Totp.CheckBase32(textBoxSecret.Text)) { secret = textBoxSecret.Text; t1 = (int)numericUpDown2.Value; digit = (int)numericUpDown1.Value; totp = new Totp(secret, t1, digit); qrCodeImgControl.Text = "otpauth://totp/" + textBoxLable.Text + ":" + textBoxUser.Text + "?secret=" + textBoxSecret.Text + "&issuer=" + textBoxLable.Text; toolTip1.SetToolTip(qrCodeImgControl, qrCodeImgControl.Text); } else { MessageBox.Show("The secret is not Base32 encoded", "TOTP GUI", MessageBoxButtons.OK, MessageBoxIcon.Error); } }