Csharp .NET Maui 滑动删除功能未删除

以下是MainPage.xaml的XAML代码:

    <?xml version="1.0" encoding="utf-8" ?>
    <ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
                 xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
                 x:Class="mauiApp.MainPage"
                 xmlns:viewmodel="clr-namespace:mauiApp.ViewModel"
                 x:DataType="viewmodel:MainViewModel">
    
        <Grid RowDefinitions="100, Auto, *"
              ColumnDefinitions=".75*,.25*"
              Padding="10"
              RowSpacing="10"
              ColumnSpacing="10">
            
            <Image Grid.ColumnSpan="2"
                   Source="dotnet_bot.png"
                   BackgroundColor="Transparent"/>
    
            <Entry Placeholder="Enter task"
                   Text="{Binding Text}"
                   Grid.Row="1"/>
    
            <Button Text="Add"
                    Command="{Binding AddCommand}"
                    Grid.Row="1"
                    Grid.Column="1"/>
            
            <CollectionView Grid.Row="2" 
                            Grid.ColumnSpan="2"
                            ItemsSource="{Binding Items}">
    
                <CollectionView.ItemTemplate>
                    <DataTemplate x:DataType="{x:Type x:String}">
                        <SwipeView>
                            <SwipeView.RightItems>
                                <SwipeItem Text="Delete"
                                           BackgroundColor="Red"
                                           Command="{Binding Source={RelativeSource AncestorType={x:Type viewmodel:MainViewModel}},Path=DeleteCommand}"
                                           CommandParameter="{Binding .}"/> 
                            </SwipeView.RightItems>
                            <Grid Padding="0,5">
                                <Frame>
                                    <Label Text="{Binding .}"
                                           FontSize="24"/>
                                </Frame>
                            </Grid>
                        </SwipeView>
                    </DataTemplate>
                </CollectionView.ItemTemplate>
            </CollectionView>
        </Grid>
    </ContentPage>

以下是MainViewModel.cs的C#代码:

using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Input;
using System.Collections.ObjectModel;

namespace mauiApp.ViewModel
{

    public partial class MainViewModel : ObservableObject
    {
        public MainViewModel()
        {
            Items = new ObservableCollection<string>();
        }

        [ObservableProperty]
        ObservableCollection<string> items;

        [ObservableProperty]
        string text;

        [RelayCommand]
        void Add()
        {
            if(string.IsNullOrWhiteSpace(Text)) 
            { 
                return; 
            }
            Items.Add(Text);
            Text = string.Empty;
        }

        [RelayCommand]
        void Delete(string s)
        {
            if (Items.Contains(s))
            {
                Items.Remove(s);
            }

        }
    }
}

以下是MainProgram.cs的C#代码:

using mauiApp.ViewModel;

namespace mauiApp;

public static class MauiProgram
{
    public static MauiApp CreateMauiApp()
    {
        var builder = MauiApp.CreateBuilder();
        builder
            .UseMauiApp<App>()
            .ConfigureFonts(fonts =>
            {
                fonts.AddFont("OpenSans-Regular.ttf", "OpenSansRegular");
                fonts.AddFont("OpenSans-Semibold.ttf", "OpenSansSemibold");
            });

        builder.Services.AddSingleton<MainPage>();
        builder.Services.AddSingleton<MainViewModel>();
        return builder.Build();
    }
}

以下是MainPage.xaml.cs的C#代码:

using mauiApp.ViewModel;

namespace mauiApp

public partial class MainPage : ContentPage
{
    public MainPage(MainViewModel vm)
    {
        InitializeComponent();
        BindingContext = vm;
    }
}

我正在努力学习毛伊语，我从YouTube频道的DotNet教程中复制了以下代码.然而，CollectionView中的滑动到删除功能并未按预期工作:

• 当我滑动并点击"Delete"时，该项不会从集合中移除，Delete方法也不会被击中.