WPF交互请求始终为null

嗨，我是WPF和XAML的新手，我正试图利用MVVMCross的MvxInteraction与用户交互，以获得一个"；"是"；或"；否"；基于此示例的确认。

我在让交互订阅事件处理程序时遇到了一个障碍，因为交互总是空的。我可以从引用中看到，交互变量基于绑定相互查看，所以我不确定发生了什么。我四处查看了一下，发现了这一点，这表明我稍后可以将绑定带到代码后面的UserControl视图中，所以我使用了一个调度器，但这也不起作用。

查看模型

public class StudentDetailsViewModel : MvxViewModel
{
private InteractionRequest<YesNoQuestion> _interaction = new InteractionRequest<YesNoQuestion>();
public IInteractionRequest Interaction => _interaction;
}

VIEW.XAML.CS

public partial class StudentDetailsView : MvxWpfView
{
private InteractionRequest<YesNoQuestion> _interaction;
public StudentDetailsView()
{
InitializeComponent();
Dispatcher.BeginInvoke(new Action(() => BindInteractions()), DispatcherPriority.ContextIdle, null);
}
public InteractionRequest<YesNoQuestion> Interaction
{
get => _interaction;
set
{
if(_interaction != null)
{
_interaction.Requested -= OnInteractionRequested;
}
_interaction = value;
_interaction.Requested += OnInteractionRequested; //***RUN TIME NULL EXCEPTION***
}
}
private void OnInteractionRequested(object sender, InteractionRequestedEventArgs eventArgs)
{
var yesNoQuestion = eventArgs.Callback;
}
private void BindInteractions()
{
var set = this.CreateBindingSet<StudentDetailsView, StudentDetailsViewModel>();
set.Bind(this).For(view => view.Interaction).To(viewModel => viewModel.Interaction).OneWay();
set.Apply();
}
}

交互类

public class YesNoQuestion
{
public bool? Confirmation { get; set; }
public string Question { get; set; }
public YesNoQuestion(string message)
{
Question = message;
}
}

我的第二个问题是，我对他们用"；ShowDialog"；以及"；对话框状态"；这里是他们的例子：

private async void OnInteractionRequested(object sender, MvxValueEventArgs<YesNoQuestion> eventArgs)
{
var yesNoQuestion = eventArgs.Value;
// show dialog
var status = await ShowDialog(yesNoQuestion.Question);
yesNoQuestion.YesNoCallback(status == DialogStatus.Yes);
}

他们只是简单地调用另一个用户控件视图来通过ShowDialog方法显示自己吗？