private void OnSelectionChanged(object sender, SelectionChangedEventArgs e)
{
if (e == null)
{
return;
}
var previousCol = _SelectedCascade;
_SelectedCascade = (sender as DataTemplates.CascadeComponentXaml)?.Column ?? -1;
ICard top = (_SelectedCascade >= 0) ? _Cards[_SelectedCascade].LastOrDefault() : CardEx.Empty; // card available to play of cascade (visually on bottom but called top)
ICard previous = null;
foreach (var c in _Cards?.SelectMany(z => z)?.Where(z => z.Selected))
{
//if (c.Selected) previous = c;
c.Selected = false;
}
previous = _SelectedCard;
var current = e.CurrentSelection.FirstOrDefault() as ICard;
if ((current != null) && (top == current)) // only allow top card in cascade to be selected
{
current.Selected = true;
}
if (previous == CardEx.Empty)
{
this.BackgroundColor = Color.Gray; // nothing previously selected
}
else if (previous == current)
{
this.BackgroundColor = Color.Gray; // same card
}
else if (previous.CanBePlacedOnSingle(current))
{
this.BackgroundColor = Color.Green; // move is valid
}
else
{
this.BackgroundColor = Color.Yellow; // invalid move
}
_SelectedCard = current;
RefreshView();
}
