static void stock_PriceChanged(object sendor, PriceChangedEventArgs e)
{
if ((e.NewPrice - e.LastPrice) / e.LastPrice > 0.1M)
{
Console.WriteLine("Alert, 10% stock price increase!");
}
}
protected virtual void OnPriceChanged(PriceChangedEventArgs e)
{
PriceChanged?.Invoke(this, e);
}