MAUI - 类型或命名空间名称“平台”在命名空间中不存在

尝试将我的导航栏移动到 MAUI 屏幕底部，但这并不像我想象的那么简单。

我正在按照这篇文章的解决方案：这里

然而，我得到了The type or namespace name 'Platforms' does not exist in the namespace 'Project' (are you missing an assembly reference?)。

此错误与此行有关 handlers.AddHandler<Shell, ShellHandler>();

我发现了几个有同样问题的帖子，但似乎没有一个提供解决方案。

有什么建议吗？

应用程序.xaml.cs

using Project._ViewModels.SharedViewModel;
using Microsoft.Maui.Hosting;
using Microsoft.Maui.Controls.Hosting;
using CommunityToolkit.Maui;
using Project.Helpers;
using Project.Platforms; ///this is where the error is


namespace Project
{
    /// <summary>
    /// Represents the main application class.
    /// </summary>
    public partial class App : Application
    {
        /// <summary>
        /// Initializes a new instance of the <see cref="App"/> class.
        /// </summary>
        public App()
        {
            InitializeComponent();
            MainPage = new AppShell();
        }

        public static MauiApp CreateMauiApp()
        {
            var builder = MauiApp.CreateBuilder();
            builder
                 .UseMauiApp<App>()
                 .UseMauiCommunityToolkit()
                 .ConfigureMauiHandlers(handlers =>
                 {
                     handlers.AddHandler<Shell, ShellHandler>();                      });

            return builder.Build();
        }
    }
}

ShellHandler.cs（路径：Project\Platforms\Android\ShellHandler.cs）

using Android.Content;
using AndroidX.CoordinatorLayout.Widget;
using Google.Android.Material.BottomNavigation;
using Microsoft.Maui.Controls.Handlers.Compatibility;
using Microsoft.Maui.Controls.Platform.Compatibility;
using Microsoft.Maui.Controls.PlatformConfiguration.AndroidSpecific;
using Svg;
using System;

namespace Project.Platforms.Android
{
    public partial class ShellHandler : ShellRenderer
    {
        public ShellHandler(Context context) : base(context) { }

        protected override IShellBottomNavViewAppearanceTracker CreateBottomNavViewAppearanceTracker(Microsoft.Maui.Controls.ShellItem shellItem)
        {
            return new ShellBottomNavViewAppearanceTracker(this, shellItem.CurrentItem);
        }

        public class ShellBottomNavViewAppearanceTrackerEx : ShellBottomNavViewAppearanceTracker
        {
            public ShellBottomNavViewAppearanceTrackerEx(IShellContext shellContext, Microsoft.Maui.Controls.ShellItem shellItem)
                : base(shellContext, shellItem) { }

            public override void SetAppearance(BottomNavigationView bottomView, IShellAppearanceElement appearance)
            {
                base.SetAppearance(bottomView, appearance);

            }
        }
    }
}