M-V-VM设计问题。从ViewModel调用视图

public class MyModel
{
    public string Text { get; set; }
}

public class MyViewModel : INotifyPropertyChanged
{
    private MyModel _model;
    private string _displayText;

    public MyViewModel(MyModel model)
    {
        _model = model;
        DisplayText = model.Text;
    }

    public string DisplayText
    {
        get => _displayText;
        set
        {
            if (_displayText != value)
            {
                _displayText = value;
                OnPropertyChanged(nameof(DisplayText));
            }
        }
    }

    public ICommand UpdateTextCommand { get; }

    public MyViewModel()
    {
        UpdateTextCommand = new RelayCommand(UpdateText);
    }

    private void UpdateText()
    {
        DisplayText = "Updated Text";
    }

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

<Window x:Class="MVVMExample.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525">
    <StackPanel>
        <TextBox Text="{Binding DisplayText}" />
        <Button Content="Update Text" Command="{Binding UpdateTextCommand}" />
    </StackPanel>
</Window>

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
        DataContext = new MyViewModel(new MyModel { Text = "Initial Text" });
    }
}