MyAvaloniaDemo/ViewModels/AppViewModel.cs

using ReactiveUI;
using System;

namespace MyAvaloniaApp.ViewModels;

/// <summary>
/// 应用程序级别的 ViewModel，实现 IScreen 接口
/// </summary>
public class AppViewModel : ReactiveObject, IScreen
{
    public RoutingState Router { get; } = new RoutingState();
    
    public AppViewModel()
    {
        // 配置路由 - 默认导航到主窗口
        // 注意：这里应该通过依赖注入获取 MainWindowViewModel
        // Router.Navigate.Execute(new MainWindowViewModel());
    }
}