private void PreviousChanged_Handler(object sender, EnableButtonEventArgs e)
{
btnBack.Enabled = e.ButtonEnabled;
btnBack.Text = string.IsNullOrEmpty(e.ButtonText) ? "< Back" : e.ButtonText;
}
private void NextChanged_Handler(object sender, EnableButtonEventArgs e)
{
btnNext.Enabled = e.ButtonEnabled;
btnNext.Text = string.IsNullOrEmpty(e.ButtonText) ? "Next >" : e.ButtonText;
}