如何将combobox与两个表wpf连接起来

<ComboBox x:Name="comboBox" ItemsSource="{Binding TableAData}" DisplayMemberPath="PropertyName" SelectedValuePath="PropertyName" />

public class ViewModel : INotifyPropertyChanged
{
    private ObservableCollection<TableA> tableAData;
    private ObservableCollection<TableB> tableBData;

    public ObservableCollection<TableA> TableAData
    {
        get { return tableAData; }
        set
        {
            tableAData = value;
            OnPropertyChanged(nameof(TableAData));
        }
    }

    public ObservableCollection<TableB> TableBData
    {
        get { return tableBData; }
        set
        {
            tableBData = value;
            OnPropertyChanged(nameof(TableBData));
        }
    }

    private TableA selectedTableAItem;
    public TableA SelectedTableAItem
    {
        get { return selectedTableAItem; }
        set
        {
            selectedTableAItem = value;
            LoadTableBData();
            OnPropertyChanged(nameof(SelectedTableAItem));
        }
    }

    public event PropertyChangedEventHandler PropertyChanged;

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

    private void LoadTableAData()
    {
        // 从数据库或其他数据源获取TableA的数据，并赋值给TableAData
        TableAData = new ObservableCollection<TableA>(yourTableAData);
    }

    private void LoadTableBData()
    {
        // 根据SelectedTableAItem的值，从数据库或其他数据源获取TableB的数据，并赋值给TableBData
        TableBData = new ObservableCollection<TableB>(yourTableBData);
    }
}

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
        ViewModel viewModel = new ViewModel();
        viewModel.LoadTableAData();
        DataContext = viewModel;
    }
}

<ComboBox ItemsSource="{Binding TableBData}" DisplayMemberPath="PropertyName" SelectedValuePath="PropertyName" />