MVVMCross ListView -如何只填充与特定条件匹配的列表项？

using MvvmCross.ViewModels;
using System.Collections.ObjectModel;

public class MyViewModel : MvxViewModel
{
    private ObservableCollection<MyItem> _items;
    public ObservableCollection<MyItem> Items
    {
        get => _items;
        set => SetProperty(ref _items, value);
    }

    private string _filter;
    public string Filter
    {
        get => _filter;
        set
        {
            SetProperty(ref _filter, value);
            FilterItems();
        }
    }

    public MyViewModel()
    {
        // 初始化Items
        Items = new ObservableCollection<MyItem>
        {
            new MyItem { Name = "Item 1", Category = "Category A" },
            new MyItem { Name = "Item 2", Category = "Category B" },
            new MyItem { Name = "Item 3", Category = "Category A" }
        };
    }

    private void FilterItems()
    {
        // 根据筛选条件过滤Items
        var filteredItems = string.IsNullOrEmpty(Filter) ? Items : new ObservableCollection<MyItem>(Items.Where(i => i.Category == Filter));
        Items = filteredItems;
    }
}

public class MyItem
{
    public string Name { get; set; }
    public string Category { get; set; }
}

<StackLayout>
    <Entry Text="{Binding Filter}" Placeholder="Filter by category" />
    <ListView ItemsSource="{Binding Items}">
        <ListView.ItemTemplate>
            <DataTemplate>
                <TextCell Text="{Binding Name}" />
            </DataTemplate>
        </ListView.ItemTemplate>
    </ListView>
</StackLayout>