private void OnPromotionSelected(PromotionSelectedEventArgs e)
        {
            var handler = promotionSelected;

            if (handler != null)
            {
                handler.Invoke(this, e);
            }
        }
 /// <summary>
 /// The event handler for OnPromotionSelection.
 /// </summary>
 /// <param name="sender">The event sender.</param>
 /// <param name="e">The event arguments.</param>
 private void PromotionWindow_OnPromotionSelection(object sender, PromotionSelectedEventArgs e)
 {
     CalculateBitboard(e.Move, _quiescenceSearch);
     PromotionWindow.Hide();
 }