private void AddNewSponsor(object sender, RoutedEventArgs e) { var addPersonView = new AddPersonView(); addPersonView.ShowDialog(); if (addPersonView.DialogResult.HasValue && addPersonView.DialogResult.Value) { context.Persons.Add(addPersonView.Person); this.Runner.Sponsors.Add(new RunnerSponsor { Betrag = 0, Runner = this.Runner, Sponsor = addPersonView.Person }); } }