private void AddMonsterButton_Click(object sender, RoutedEventArgs e) { try { Monster newMonster = new Monster(MonsterCRSelector.Text, Convert.ToInt32(NumMonstersTextBox.Text)); monsterList.AddtoMonsterList(newMonster); //add entry to the monster listbox and determine the output string based on number of monsters ListBoxItem item = new ListBoxItem(); if (newMonster.GetNumberOfMonsters() > 1) { item.Content = Convert.ToString(newMonster.GetNumberOfMonsters()) + " monsters with a CR of " + newMonster.GetChallengeRating(); } else { item.Content = Convert.ToString(newMonster.GetNumberOfMonsters()) + " monster with a CR of " + newMonster.GetChallengeRating(); } MonsterListBox.Items.Add(item); //determine if CalculateXPButton should be enabled if (AllListsAreNotEmpty(characterList, monsterList)) { CalculateXPButton.IsEnabled = true; AddToEncounterListButton.IsEnabled = true; } } catch (Exception ex) { MessageBox.Show(ex.Message); } }