WPF MVVM 模式下通过消息机制获取自定义对话框数据

public class OpenDialogMessage : RequestMessage<string> { }

public partial class MainWindowViewModel : ObservableObject
{
    [RelayCommand]
    private void OpenDialog()
    {
        var result = WeakReferenceMessenger
            .Default.Send<OpenDialogMessage>();
        
        if (result != null)
        {
            Console.Out.WriteLine("result = {0}", result.Response);
        }
    }
}

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();

        DataContext = new MainWindowViewModel();
        
        WeakReferenceMessenger.Default
            .Register<MainWindow, OpenDialogMessage>(this, (receiver, message) => { });
    }
}

public partial class MainWindow : Window
{
    public MainWindow()
    {
        // --- 省略已有代码 ---
        
        WeakReferenceMessenger.Default
            .Register<MainWindow, OpenDialogMessage>(this, (receiver, message) =>
        {
            var dialog = new DialogWindow();
            
            // 添加窗口关闭事件
            dialog.Closed += (s, e) =>
            {
                var w = s as DialogWindow;
                message.Reply(w?.InputText.Text);
            };
			
            // 打开模态对话框
            dialog.ShowDialog();
        });
    }
}