FavFighters.xaml.cs

public partial class FavFightersView : ContentPage
{
    public FavFightersView()
    {
        InitializeComponent();
        BindingContext = new FavFightersViewModel();
    }

    // !!!!! This is the important part, right here !!!!!
    void SwipeItemView_Invoked(System.Object sender, System.EventArgs e)
    {
        var selectedFighter = ((SwipeItemView)sender).BindingContext as Fighter;
        
        DisplayAlert("Added favorite", $"{selectedFighter.Name} is added to your favorites!", "Thanks");
    }
}