Csharp 为什么我的UserControl没有加载到我的主窗口中

我正在try 将我的应用程序设置为根据设备的名称显示不同的视图.不幸的是，我似乎无法加载View，尽管正在调用ViewModel.我不完全确定我错过了什么.

目前，当应用程序加载时，唯一显示的是主窗口，但没有在其中加载视图.

如何加载视图？

这是我的MainWindow.axaml:

<Window
    xmlns="https://github.com/avaloniaui"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:vm="clr-namespace:TAStagingApp.ViewModels.Implementations;assembly=TAStagingApp.ViewModels"
    mc:Ignorable="d"
    d:DesignWidth="800"
    d:DesignHeight="450"
    x:Class="TAStagingApp.Views.MainWindow"
    x:DataType="vm:MainWindowViewModel"
    Background="{StaticResource TABackgroundColor}"
    Icon="/Assets/tastaging.png"
    WindowStartupLocation="CenterScreen"
    Title="TA Staging">

    <Design.DataContext>
        <vm:MainWindowViewModel />
    </Design.DataContext>
    <Grid>
        <ContentPresenter Name="StagingContent"/>
    </Grid>

</Window>

和MainWindow.axaml.cs

namespace TAStagingApp.Views;
public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
        DataContext = this;
    }

    public void SetContent(Control control)
    {
        var mainContent = this.FindControl<ContentPresenter>("StagingContent");
        mainContent!.Content = control;
    }
}

App.axaml.cs

using AvaloniaApplication = Avalonia.Application;

namespace TAStagingApp;
public partial class App : AvaloniaApplication
{
    public override void Initialize()
    {
        AvaloniaXamlLoader.Load(this);
    }

    public override void OnFrameworkInitializationCompleted()
    {
        var viewModelLoader = new ViewModelLoader(new MainWindow());
        ServiceLocator.Initialize(viewModelLoader);

        if (ApplicationLifetime is IClassicDesktopStyleApplicationLifetime desktop)
        {
            DataContext = GetRequiredService<IMainWindowViewModel>();
            desktop.MainWindow = new MainWindow
            {
                DataContext = DataContext,
            };

            viewModelLoader.LoadContentViewBasedOnComputerName();
        }

        base.OnFrameworkInitializationCompleted();
    }

    private static T GetRequiredService<T>() => Locator.Current.GetRequiredService<T>();
}

ViewModelLoader.cs

namespace TAStagingApp.DependencyInjection.Loaders;
public sealed class ViewModelLoader(MainWindow mainWindow) : IViewModelLoader
{
    private readonly MainWindow _mainWindow = mainWindow;

    public void LoadContentViewBasedOnComputerName()
    {
        var serviceProvider = DeviceTypeHelper.GetDeviceTypeServiceProvider();
        var deviceType = DeviceTypeHelper.GetDeviceType(serviceProvider);

        Control contentView = deviceType.Value.ToString() switch
        {
            var device when device.Equals(DeviceType.Server.ToString()) => new ServerConfigureView(),
            var device when device.Equals(DeviceType.Terminal.ToString()) => new TerminalConfigureView(),
            var device when device.Equals(DeviceType.Kitchen.ToString()) => new TerminalConfigureView(),
            _ => new AdminView()
        };

        _mainWindow.SetContent(contentView);
    }
}

MainWindowViewModel.cs

namespace TAStagingApp.ViewModels.Implementations;

public class MainWindowViewModel : ViewModelBase, IMainWindowViewModel
{
    public MainWindowViewModel(IActivateViewModel viewModel)
    {
        if (viewModel.GetType() == typeof(TerminalConfigureViewModel))
        {
            TerminalConfigureViewModel = viewModel;
        }
        else if (viewModel.GetType() == typeof(ServerConfigureViewModel))
        {
            ServerConfigureViewModel = viewModel;
        }
        else
        {
            AdminViewModel = viewModel;
        }

        Activate(viewModel);
    }

    public MainWindowViewModel()
    {
    }

    public IActivateViewModel AdminViewModel { get; } = default!;

    public IActivateViewModel TerminalConfigureViewModel { get; } = default!;

    public IActivateViewModel ServerConfigureViewModel { get; } = default!;

    private static void Activate(IActivateViewModel viewModel)
        => viewModel.Activate();
}

我已经看了这两天了，我不知道我错过了什么.

谢谢