C# 如何在另一个xaml中显示搜索栏列表的结果？

我想在另一个xml页面中显示搜索结果。如本计划所述：

搜索栏所在的页面具有以下xml代码：

 <SearchBar SearchButtonPressed="SearchBar_SearchButtonPressed"

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哪一行抛出异常？该行的哪个特定元素为空？在解决问题之前，您需要弄清楚这是行EmployeeListView.ItemsSource=_container.MyListCollector.Where（u=>u.nome.ToLower（）.Contains（e.NewTextValue.ToLower（））| u.cognome.ToLower（）.Contains（e.NewTextValue.ToLower（））；这一行中有十几个东西可能是空的-哪一个是空的？我不知道我没有报告主题，但是整行你需要使用调试器来找出它。我们没办法帮你。如果您不知道如何使用调试器（您应该学习），您可以在执行该行之前添加代码来测试每个元素的null值。

 public partial class FriendsPage : ContentPage
{
    public FriendsPage()
    {
        InitializeComponent();
        Xamarin.Forms.NavigationPage.SetHasNavigationBar(this, false);
        On<Xamarin.Forms.PlatformConfiguration.iOS>().SetUseSafeArea(true);
    }

    private void SearchBar_SearchButtonPressed(object sender, EventArgs e)
    {
        var search = sender as SearchBar;
        this.Navigation.PushModalAsync(new SearchBarFriends(search.Text), true);
    }
}

public partial class SearchBarFriends : ContentPage
{
    public SearchBarFriends()
    {
        InitializeComponent();
    }

    public SearchBarFriends(String key)
    {
        InitializeComponent();
        searchBar.Text = key;
        Xamarin.Forms.NavigationPage.SetHasNavigationBar(this, false);
        On<Xamarin.Forms.PlatformConfiguration.iOS>().SetUseSafeArea(true);

        BindingContext = new MyListViewModelUser();
    }

    async void Handle_ItemTapped(object sender, Xamarin.Forms.ItemTappedEventArgs e)
    {
        DbConnectionClass db = new DbConnectionClass();
        User u = e.Item as User;
        int id = db.QueryId("SELECT id FROM thewishlist.user WHERE nome='" + u.nome + "'OR cognome='" + u.cognome +"'");

        var friendsCorrenteJson = JsonConvert.SerializeObject(u);
        App.Current.Properties["friends"] = friendsCorrenteJson;
        await App.Current.SavePropertiesAsync();
        await Navigation.PushAsync(new ProfileFriend(u));

        db.CloseConnection();

    }

    //clicked on searchbar
    void Handle_TextChanged(object sender, TextChangedEventArgs e)
    {
        var search = sender as SearchBar;
        var _container = BindingContext as MyListViewModelUser;
        EmployeeListView.BeginRefresh();

        if (string.IsNullOrWhiteSpace(e.NewTextValue))
            EmployeeListView.ItemsSource = _container.MyListCollector;
        else
        {
            EmployeeListView.ItemsSource = _container.MyListCollector.Where(
                u => u.nome.ToLower().Contains(e.NewTextValue.ToLower()) || u.cognome.ToLower().Contains(e.NewTextValue.ToLower()));
        }
        EmployeeListView.EndRefresh();
    }
}

<SearchBar x:Name="searchBar" Placeholder="Friends..." FontAttributes="Italic" PlaceholderColor="Silver" TextChanged="Handle_TextChanged" BackgroundColor="#FFFC79" HorizontalOptions="Start"  VerticalOptions="Start" CancelButtonColor="Black"/>
         <ListView ItemsSource="{Binding MyListCollector}" IsPullToRefreshEnabled="true" x:Name="EmployeeListView" HasUnevenRows="true" ItemTapped="Handle_ItemTapped" >
        <ListView.ItemTemplate>

 EmployeeListView.ItemsSource = _container.MyListCollector.Where(
                u => u.nome.ToLower().Contains(e.NewTextValue.ToLower()) || u.cognome.ToLower().Contains(e.NewTextValue.ToLower()));