用MVVM处理WPF中的对话框

public class DialogData
{
    public string Message { get; set; }
    public bool IsConfirmed { get; set; }
}

public class DialogViewModel : INotifyPropertyChanged
{
    private DialogData _dialogData;
    public DialogData DialogData
    {
        get { return _dialogData; }
        set
        {
            _dialogData = value;
            OnPropertyChanged(nameof(DialogData));
        }
    }

    public ICommand ConfirmCommand { get; }

    public DialogViewModel()
    {
        DialogData = new DialogData { Message = "Are you sure?" };
        ConfirmCommand = new RelayCommand(OnConfirm);
    }

    private void OnConfirm()
    {
        DialogData.IsConfirmed = true;
    }

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

<Window x:Class="MVVMDialogDemo.DialogWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="DialogWindow" Height="200" Width="300">
    <StackPanel>
        <TextBlock Text="{Binding DialogData.Message}" />
        <Button Content="Confirm" Command="{Binding ConfirmCommand}" />
    </StackPanel>
</Window>

public partial class DialogWindow : Window
{
    public DialogWindow(DialogViewModel viewModel)
    {
        InitializeComponent();
        DataContext = viewModel;
    }
}

public class DialogViewModel : INotifyPropertyChanged
{
    // ...

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

public class RelayCommand : ICommand
{
    private readonly Action<object> _execute;
    private readonly Predicate<object> _canExecute;

    public RelayCommand(Action<object> execute, Predicate<object> canExecute = null)
    {
        _execute = execute ?? throw new ArgumentNullException(nameof(execute));
        _canExecute = canExecute;
    }

    public bool CanExecute(object parameter)
    {
        return _canExecute == null || _canExecute(parameter);
    }

    public void Execute(object parameter)
    {
        _execute(parameter);
    }

    public event EventHandler CanExecuteChanged
    {
        add { CommandManager.RequerySuggested += value; }
        remove { CommandManager.RequerySuggested -= value; }
    }
}