public async void CheckInBook() { if (!PerformCheckInValidation()) { DisplayErrorMessage(BookCheckInConditionError); return; } var transaction = new BookTransaction { Customer = new Customer { CustomerId = SuppliedCustomerId }, Book = new Book { BookId = SelectedBook.BookId }, CheckIn = DateTime.Now }; bool success = await bookManager.CheckInBook(transaction).ConfigureAwait(false); SuppliedCustomerId = 0; OnPropertyChanged("SuppliedCustomerId"); if (success) { ++SelectedBook.AvailableCopies; CollectionViewSource.GetDefaultView(this.Books).Refresh(); DisplayInfoMessage(BookCheckInSuccess, "Success!"); } else { DisplayErrorMessage(BookCheckInError); } }