与 ObservableCollection 绑定的组合框未更新

Question

我正在尝试在删除一个项目时更新组合框，但我无法让它工作。
我正在将 ObservableCollection 表单填充为 XML，然后将其绑定到组合框，这部分工作得很好。 当我单击删除按钮时，我正在从 xml 中删除，并且我不知道如何触发从可观察集合中删除。

这是我目前的尝试：

ChargementScenario.Xaml

<ComboBox x:Name="cbScenario" ItemsSource="{Binding Scenarios, Mode=TwoWay}" DisplayMemberPath="name" Foreground="Black"
                    HorizontalAlignment="Center" VerticalAlignment="Center" Width="250" Height="40" FontFamily="/GAF-WPF;component/Resources/Font/#Barlow" 
                          Grid.Row="0" Grid.Column="1" SelectionChanged="CbScenario_SelectionChanged">
                </ComboBox>

ChargementScenario.xaml.cs

public partial class pageChargementScenario : Page
    {
        ObservableCollection<Scenario> listScenario = new ObservableCollection<Scenario>();
        public pageChargementScenario()
        {
            InitializeComponent();

            Loaded += pageChargementScenario_Loaded;
        }

        private void pageChargementScenario_Loaded(object sender, RoutedEventArgs e)
        {
            //VERIFICATION DE LA PRESENCE DE SCENARIO 
            ScenarioVM scenarioVM = new ScenarioVM();
            scenarioVM.Scenarios = Scenario.loadListScenario();            

            if (scenarioVM.Scenarios.Count != 0)
            {
                DataContext = scenarioVM;
            }
            else
            {
                cbScenario.IsEnabled = false;
                btnLoadScenario.Visibility = Visibility.Hidden;
                btnDeleteScenario.Visibility = Visibility.Hidden;
            }
        }

private void CbScenario_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            var scenario = (Scenario)e.AddedItems[0];
            txtBoxInfoComplementaire.Text = scenario.infoComplementaire;
        }

  private void BtnDeleteScenario_Click(object sender, RoutedEventArgs e)
        {
            DialogResult result = System.Windows.Forms.MessageBox.Show($"Voulez-vous effacer le scenario {cbScenario.Text}", "SUPPRESSION SCENARIO", MessageBoxButtons.YesNo);

            if (result == DialogResult.Yes)
            {
                Scenario.deleteScenario(cbScenario.Text);
            }
        }
}

Scenario.cs

 public class Scenario
    {
        public string name { get; set; }
        public string codeClient { get; set; }
        public string codeAppli { get; set; }
        public string infoComplementaire { get; set; }
        public string modeTelecom { get; set; }
        public string extension { get; set; }
        public string destination { get; set; }
        public string idf { get; set; }
        public string modeEnvoieFtp { get; set; }
        public string typeErreur { get; set; }
        public string partenaire { get; set; }
        public int nombreFichier { get; set; }
        public int intervalleFichier { get; set; }
        public int nombreErreur { get; set; }

        public Scenario()
        {
        }

        public Scenario(string Name, string CodeClient, string CodeAppli, string InfoComplementaire, string ModeTelecom, string Idf, string Partenaire, string Extension, string Destination,
            int NombreFicher, string TypeErreur, int NombreErreur, int IntervalleFichier, string ModeEnvoieFtp)
        {
            name = Name;
            codeClient = CodeClient;
            codeAppli = CodeAppli;
            infoComplementaire = InfoComplementaire;
            modeTelecom = ModeTelecom;
            extension = Extension;
            destination = Destination;
            idf = Idf;
            modeEnvoieFtp = ModeEnvoieFtp;
            typeErreur = TypeErreur;
            partenaire = Partenaire;
            nombreFichier = NombreFicher;
            intervalleFichier = IntervalleFichier;
            nombreErreur = NombreErreur;
        }

        //CHARGEMENT DE LA LISTE DES SCENARIOS
        public static ObservableCollection<Scenario> loadListScenario()
        {
            XDocument xmlScenario = new XDocument();
            if (File.Exists(ConfigurationManager.AppSettings["xmlScenario"]))
            {
                xmlScenario = XDocument.Load(ConfigurationManager.AppSettings["xmlScenario"]);

                //CHARGEMENT DES SCENARIOS
                IEnumerable<Scenario> listeScenario = from scenario in xmlScenario.Descendants("scenario")
                                                      select new Scenario()
                                                      {
                                                          name = (string)scenario.Attribute("nom"),
                                                          codeClient = (string)scenario.Element("codeClient"),
                                                          codeAppli = (string)scenario.Element("codeApplication"),
                                                          infoComplementaire = (string)scenario.Element("informationComplementaire"),
                                                          modeTelecom = (string)scenario.Element("modeTelecom"),
                                                          extension = (string)scenario.Element("extension"),
                                                          destination = (string)scenario.Element("destination"),
                                                          idf = (string)scenario.Element("idf"),
                                                          partenaire = (string)scenario.Element("partenaire"),
                                                          nombreFichier = (int)scenario.Element("nombreFichier"),
                                                          typeErreur = (string)scenario.Element("typeErreur"),
                                                          nombreErreur = (int)scenario.Element("nombreErreur"),
                                                          intervalleFichier = (int)scenario.Element("intervalleFichier"),
                                                          modeEnvoieFtp = (string)scenario.Element("modeEnvoieFtp")
                                                      };

                ObservableCollection<Scenario> collectionScenario = new ObservableCollection<Scenario>(listeScenario);

                return collectionScenario;
            }
            else
            {
                return null;
            }
        }

        public static bool checkDoublon(string scenarioName)
        {
            bool exist = false;

            XDocument xmlScenario = new XDocument();
            xmlScenario = XDocument.Load(ConfigurationManager.AppSettings["xmlScenario"]);

            if (File.Exists(ConfigurationManager.AppSettings["xmlScenario"]))
            {
                exist = xmlScenario.Elements("listScenario").Elements("scenario")
                           .Any(x => x.Attribute("nom").Value == scenarioName);
            }
            return exist;
        }

        public static void saveScenario(Scenario scenario)
        {
            XDocument xmlScenario = new XDocument();

            //CREATION DU XML SI CELUI CI N'EXISTE PAS
            if (!File.Exists(ConfigurationManager.AppSettings["xmlScenario"]))
            {
                xmlScenario = new XDocument(new XElement("listScenario"));
                xmlScenario.Save(ConfigurationManager.AppSettings["xmlScenario"]);
            }

            //CHECK SI LE SCENARIO EXISTE DEJA
            bool scenarioExist = checkDoublon(scenario.name);

            if (scenarioExist)
            {
                MessageBox.Show("UN SCENARIO DU MEME NOM EXISTE DEJA", "ERREUR NOM SCENARIO");
                return;
            }

            //AJOUT DU NOUVEAU SCENARIO
            xmlScenario = XDocument.Load(ConfigurationManager.AppSettings["xmlScenario"]);

            XElement newScenario = new XElement("scenario", new XAttribute("nom", scenario.name),
            new XElement("codeClient", scenario.codeClient),
            new XElement("codeApplication", scenario.codeAppli),
            new XElement("informationComplementaire", scenario.infoComplementaire),
            new XElement("modeTelecom", scenario.modeTelecom),
            new XElement("idf", scenario.idf),
            new XElement("partenaire", scenario.partenaire),
            new XElement("extension", scenario.extension),
            new XElement("destination", scenario.destination),
            new XElement("nombreFichier", scenario.nombreFichier),
            new XElement("typeErreur", scenario.typeErreur),
            new XElement("nombreErreur", scenario.nombreErreur),
            new XElement("intervalleFichier", scenario.intervalleFichier),
            new XElement("modeEnvoieFtp", scenario.modeEnvoieFtp)
            );

            xmlScenario.Root.AddFirst(newScenario);
            xmlScenario.Save(ConfigurationManager.AppSettings["xmlScenario"]);

        }

        public static void deleteScenario(string scenarioName)
        {
            XDocument xmlScenario = new XDocument();
            xmlScenario = XDocument.Load(ConfigurationManager.AppSettings["xmlScenario"]);

            if (File.Exists(ConfigurationManager.AppSettings["xmlScenario"]))
            {
                var elementToRemove = xmlScenario.Elements("listScenario").Elements("scenario")
                           .Where(x => x.Attribute("nom").Value == scenarioName);
                elementToRemove.Remove();

                xmlScenario.Save(ConfigurationManager.AppSettings["xmlScenario"]);
            }
        }


    }

ScenarioVM.cs

    public class ScenarioVM : INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged;
        protected void OnPropertyChanged(string name)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(name));
        }
        private ObservableCollection<Scenario> _Scenarios { get; set; }
        public ObservableCollection<Scenario> Scenarios
        {
            get { return _Scenarios; }
            set {
                _Scenarios = value;
                OnPropertyChanged("Scenario");
            }
        }
}

我正在尝试使用 MVVC，但我对此很陌生，所以......我不知道我错过了什么......

提前谢谢 :)

Answer 1

为了从源集合中删除选定的元素，您需要访问视图模型，方法是将DataContext 属性强制转换为视图模型类型，或者将引用保留为类成员（例如私有字段private ScenarioVM scenarioVM;)

if (result == DialogResult.Yes)
{
    var selectedScenario = cbScenario.SelectedItem as Scenario;

    if (selectedScenario != null)
    {
        var scenarioVM = (ScenarioVM)DataContext;
        scenarioVM.Scenarios.Remove(selectedScenario);

        Scenario.deleteScenario(selectedScenario.name);
    }
}

---

请注意，您的 Scenario 类应遵守广泛接受的命名约定，并将 PascalCase 用于属性名称，使用 camelCase 用于局部变量和方法参数名称：

public class Scenario
{
    public string Name { get; set; }
    ...
    public Scenario(string name, ...)
    {
        Name = name;
        ...
    }
}