MVVM ComboBox绑定和添加到组合框

public class MyViewModel : INotifyPropertyChanged
{
    private ObservableCollection<string> _comboBoxItems;
    private string _selectedItem;

    public ObservableCollection<string> ComboBoxItems
    {
        get { return _comboBoxItems; }
        set
        {
            _comboBoxItems = value;
            OnPropertyChanged(nameof(ComboBoxItems));
        }
    }

    public string SelectedItem
    {
        get { return _selectedItem; }
        set
        {
            _selectedItem = value;
            OnPropertyChanged(nameof(SelectedItem));
        }
    }

    public MyViewModel()
    {
        ComboBoxItems = new ObservableCollection<string>();
        // 添加ComboBox的选项数据
        ComboBoxItems.Add("选项1");
        ComboBoxItems.Add("选项2");
        ComboBoxItems.Add("选项3");
    }

    // 实现INotifyPropertyChanged接口
    public event PropertyChangedEventHandler PropertyChanged;

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

<ComboBox ItemsSource="{Binding ComboBoxItems}" SelectedValue="{Binding SelectedItem}" />