private void SaveEditLeagueBtn_Click(object sender, RoutedEventArgs e)
{
League.Name = LeagueName;
League.TeamIds = Teams.Select(x => x.Id).ToList();
_leagueService.Edit(League, LeagueName, Teams.Select(x => x.Id).ToList());
MainPage.Leagues.Remove(League);
MainPage.Leagues.Add(League);
NavigationService?.GoBack();
}