formssignin.aspx.cs-1

protected void SubmitButton_Click( object sender, EventArgs e )
{
    try
    {
        if(!PINTextBox.Text.Equals("12345")) {
            ErrorTextLabel.Visible = true;
            ErrorTextLabel.Text = "Wrong PIN"
            return;
        }

        // PIN was ok, let's continue with SignIn
        SignIn( UsernameTextBox.Text, PasswordTextBox.Text );
    }
    catch ( AuthenticationFailedException ex )
    {
        HandleError( ex.Message );
    }
}