Несколько представлений используют одну и ту же ViewModel

Я написал приложение WPF. Он имеет следующие представления:

1. AddStockView.cs (используется для добавления акций)
2. StockBox.cs (представляет собой поле со списком, в котором отображаются все акции).
3. View.cs (для MainWindow.xaml)

Конечно, у каждого представления есть файл xaml. Оба представления должны быть связаны с классом ViewModel. Чтобы убедиться, что DataContext обоих представлений указывает на один и тот же объект ViewModel, я передал его в качестве параметра конструктора. Я компилирую приложение в коде Visual Studio. Компиляция работает, но окно не запускается. Наверное, мой подход неверен. Я хотел спросить вас, что мне нужно изменить, чтобы приложение работало правильно. App.xaml.cs

namespace analyser
{
    /// <summary>
    /// Interaction logic for App.xaml
    /// </summary>
    public partial class App : Application
    {
        // Statische SQLiteConnection-Instanz für die gesamte Anwendung
        public static StockDBContext stockDBContext = new StockDBContext();
        protected override void OnStartup(StartupEventArgs e)
        {
            base.OnStartup(e);
            ViewModel viewModel = new ViewModel();
            StockBoxView stockboxview = new StockBoxView(viewModel);
            AddStockView addstockview = new AddStockView(viewModel);
            
            // Methode zum Hinzufügen von Stock-Objekten in die Datenbank
            stockDBContext.Stocks.Add(new Stock { Wkn = "123456", Titel = "Porsche Automobil Holding" });
            stockDBContext.Stocks.Add(new Stock { Wkn = "654321", Titel = "PayPal" });
            stockDBContext.SaveChanges();


        }
        protected override void OnExit(ExitEventArgs e)
        {
            base.OnExit(e);
        }
}   
       
}

Просмотр 1 AddStockView.cs

namespace analyser
{
    public partial class AddStockView : UserControl
    {
   
        public AddStockView(ViewModel vm)
        {
            InitializeComponent();
            this.DataContext = vm;
        }        
    }  
}

<UserControl x:Class = "analyser.AddStockView"
             xmlns = "http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x = "http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc = "http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d = "http://schemas.microsoft.com/expression/blend/2008" 
             xmlns:local = "clr-namespace:analyser">
    <Grid>
        <StackPanel HorizontalAlignment = "Left" VerticalAlignment = "Top" Margin = "10">
            <!-- Überschrift "Add new Stocks" -->
            <TextBlock Text = "Add new Stocks" FontSize = "20" FontWeight = "Bold" Margin = "0,0,0,20" />

            <!-- TextBox für den Namen des Wertpapiers -->
            <StackPanel Orientation = "Horizontal" VerticalAlignment = "Center">
                <Label Content = "Name des Wertpapiers:" FontSize = "16" Width = "200" />
                <TextBox x:Name = "TitelTextBox" Width = "200" Margin = "10,0" FontSize = "16" Text = "{Binding Titel, UpdateSourceTrigger=PropertyChanged}" />
            </StackPanel>

            <!-- TextBox für die WKN des Wertpapiers -->
            <StackPanel Orientation = "Horizontal" VerticalAlignment = "Center">
                <Label Content = "WKN des Wertpapiers:" FontSize = "16" Width = "200" />
                <TextBox x:Name = "WknTextBox" Width = "200" Margin = "10,0" FontSize = "16" Text = "{Binding Wkn, UpdateSourceTrigger=PropertyChanged}"/>
            </StackPanel>

            <!-- Absendebutton (linksbündig) -->
            <Button Width = "150" Content = "Absenden" HorizontalAlignment = "Left" Command = "{Binding SaveCommand}" />
        </StackPanel>
    </Grid>
</UserControl>

Просмотр 2 StockBox

namespace analyser
{
    public partial class StockBoxView : UserControl
    {
        public StockBoxView(ViewModel vm)
        {
            InitializeComponent();
            this.DataContext = vm;
        }     
    }

    
}

<UserControl 
        x:Class = "analyser.StockBoxView"
         xmlns = "http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x = "http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:mc = "http://schemas.openxmlformats.org/markup-compatibility/2006" 
         xmlns:d = "http://schemas.microsoft.com/expression/blend/2008" 
         xmlns:local = "clr-namespace:analyser">
        <Grid>
             <StackPanel>
            <!-- Verwenden Sie das Binding auf die ObservableCollection<Stock> ObservableStockList -->
            <ComboBox x:Name = "StockComboBox" Width = "150" SelectedIndex = "0"
                  ItemsSource = "{Binding ObservableStockList}" 
                  DisplayMemberPath = "Titel" />
        </StackPanel>
        </Grid>
      
</UserControl>

ViewModel.cs

namespace analyser
{
    public class ViewModel : INotifyPropertyChanged
    {
        private Stock stock = new Stock();
        public ObservableCollection<Stock> ObservableStockList = new ObservableCollection<Stock>();

        private ListCollectionView ComboBoxItems;

        public ViewModel()
        {
            // Initialisierung der ObservableStockList und ComboBoxItems
            Init();
        }

        // Property für den Namen des Wertpapiers
        private string _titel;
        public string Titel
        {
            get => _titel;
            set
            {
                _titel = value;
                OnPropertyChanged(nameof(Titel));
            }
        }

        // Property für die WKN des Wertpapiers
        private string _wkn;
        public string Wkn
        {
            get => _wkn;
            set
            {
                _wkn = value;
                OnPropertyChanged(nameof(Wkn));
            }
        }

        private ICommand _saveCommand;
        
        public ICommand SaveCommand
        {
            get
            {
                if (_saveCommand == null)
                    _saveCommand = new RelayCommand(Save);
                return _saveCommand;
            }
        }

        public void Init(){

            foreach (var stock in App.stockDBContext.Stocks)
            {
                    ObservableStockList.Add(stock);
            }

             // Erstellen und Konfigurieren Sie den ListCollectionView
            ComboBoxItems = new ListCollectionView(ObservableStockList);
            ComboBoxItems.SortDescriptions.Add(new SortDescription("Titel", ListSortDirection.Ascending));
            ComboBoxItems.IsLiveSorting = true;


        }

        public void Save()
        {
            // Speichern Sie die Werte der Textboxen in das Stock-Objekt
            stock.Titel = Titel;
            stock.Wkn = Wkn;
            Console.WriteLine($"Generate new Stock with Titel {stock.Titel} and WKN {stock.Wkn}");
            App.stockDBContext.Stocks.Add(stock);
            
            // Hier können Sie die Logik zum Speichern des Stock-Objekts in die Datenbank oder an einen anderen Speicherort einfügen.
        }

        // ... (weiterer Code wie die Implementierung von INotifyPropertyChanged)
        
        public event PropertyChangedEventHandler PropertyChanged;

        protected virtual void OnPropertyChanged(string propertyName)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}

MainWindow.xaml

<Window x:Class = "analyser.View"
        xmlns = "http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x = "http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d = "http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc = "http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local = "clr-namespace:analyser"
        xmlns:uc = "clr-namespace:analyser"
        mc:Ignorable = "d"
        Title = "MainWindow" Height = "450" Width = "800">
    <Window.Resources>
        <!-- Define a style for TabItem -->
        <Style TargetType = "TabItem">
            <Setter Property = "FontSize" Value = "16" /> <!-- Set the desired font size (e.g., 16) -->
        </Style>
    </Window.Resources>
    <Grid>
        <DockPanel>
            <Menu DockPanel.Dock = "Top">
                <MenuItem Header = "_File">
                    <MenuItem Header = "_New"/>
                    <MenuItem Header = "_Open"/>
                    <Separator />
                    <MenuItem Header = "_Exit" />
                </MenuItem>
                <MenuItem Header = "_Help">
                    <MenuItem Header = "_About"/>
                </MenuItem>
            </Menu>

            <TabControl>
                <TabItem Header = "add Stock">
                    <!-- Content for Tab 1 -->
                    <uc:AddStockView/>
                </TabItem>
                <TabItem Header = "auswählen">
                    <!-- Content for Tab 1 -->
                    <uc:StockBoxView/>
                </TabItem>
                <TabItem Header = "Tab 2">
                    <!-- Content for Tab 2 -->
                    
                </TabItem>
                <TabItem Header = "Tab 3">
                    <!-- Content for Tab 3 -->
                    <TextBlock Text = "This is Tab 3 content."/>
                </TabItem>
            </TabControl>
        </DockPanel>
    </Grid>
</Window>

View.cs

namespace analyser
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class View : Window
    {
        
        public View()
        {

            InitializeBindings();
        }
        
        private void InitializeBindings() {
            DataContext = this;
        }
    }
} 

Редактировать

MyProjekt
|___Views
|    |___AddStock
|    |    |___AddStock.xaml (UserControl)
|    |    |___AddStock.xaml.cs
|    |___StockBox
|         |___StockBox.xaml (UserControl)
|         |___StockBox.xaml.cs   
|
|___ViewModels
|   |___ViewModel.cs
|
|___Models
|   |___Stock.cs
|   |___StockBoxDBContext
|
|___App.xaml
|___App.xaml.cs
|___MainWindow.xaml
|___MainWindow.xaml.cs