C# UWP：将数据从一个ListView通过数组传递至下一页的另一个ListView

Hey Mike, let's work through getting those selected DATA items from your main page's ListView over to the checkout page's ListView. Here are a few straightforward, reliable approaches tailored to your code structure:

Approach 1: Pass Selected Items via Page Constructor #

This is the simplest method for basic navigation scenarios.

1. In your main page, grab the selected items and pass them when navigating to the checkout page:

// Assuming your main ListView is named "MainListView"
var selectedItems = MainListView.SelectedItems.Cast<DATA>().ToList();

// Navigate to checkout page and pass the selected items
await Navigation.PushAsync(new CheckoutPage(selectedItems));

2. In your checkout page, modify the constructor to accept the list and bind it to your checkout ListView:

public partial class CheckoutPage : ContentPage
{
    public CheckoutPage(List<DATA> checkoutItems)
    {
        InitializeComponent();
        
        // Bind the received items to your checkout ListView (named "CheckoutListView")
        CheckoutListView.ItemsSource = checkoutItems;
    }
}

Approach 2: Use MVVM with a Shared Cart ViewModel (Recommended for Scalability) #

This keeps your code decoupled and works better for larger apps, especially if you need to access the cart items across multiple pages.

1. Create a shared CartViewModel:

using System.Collections.Generic;
using System.ComponentModel;
using System.Runtime.CompilerServices;

public class CartViewModel : INotifyPropertyChanged
{
    private List<DATA> _cartItems = new List<DATA>();
    public List<DATA> CartItems
    {
        get => _cartItems;
        set
        {
            _cartItems = value;
            OnPropertyChanged();
        }
    }

    public void AddItems(List<DATA> items)
    {
        CartItems.AddRange(items);
        OnPropertyChanged(nameof(CartItems));
    }

    public event PropertyChangedEventHandler PropertyChanged;
    protected void OnPropertyChanged([CallerMemberName] string propertyName = null)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
}

2. Register the CartViewModel as a singleton (in your App.xaml.cs):

public App()
{
    InitializeComponent();
    // Register the CartViewModel so it's accessible across pages
    DependencyService.RegisterSingleton<CartViewModel>(new CartViewModel());
    MainPage = new NavigationPage(new MainPage());
}

3. In your main page, add selected items to the cart when the user triggers checkout:

var cartViewModel = DependencyService.Get<CartViewModel>();
var selectedItems = MainListView.SelectedItems.Cast<DATA>().ToList();
cartViewModel.AddItems(selectedItems);

// Navigate to checkout page
await Navigation.PushAsync(new CheckoutPage());

4. Bind the checkout page's ListView to the CartViewModel:
   • First, create a CheckoutPageViewModel:

   public class CheckoutPageViewModel
   {
       public CartViewModel CartViewModel { get; }
   
       public CheckoutPageViewModel()
       {
           CartViewModel = DependencyService.Get<CartViewModel>();
       }
   }
   

   • Update your CheckoutPage code-behind:

   public partial class CheckoutPage : ContentPage
   {
       public CheckoutPage()
       {
           InitializeComponent();
           BindingContext = new CheckoutPageViewModel();
       }
   }
   

   • Update your checkout page XAML to bind the ListView:

   <ListView x:Name="CheckoutListView" ItemsSource="{Binding CartViewModel.CartItems}">
       <ListView.ItemTemplate>
           <DataTemplate>
               <ViewCell>
                   <StackLayout Padding="10">
                       <Label Text="{Binding Distinguisher}" FontSize="Headline" />
                       <Label Text="{Binding Price, StringFormat='${0:F2}'}" FontSize="Subtitle" />
                       <Label Text="{Binding Description}" FontSize="Body" />
                   </StackLayout>
               </ViewCell>
           </DataTemplate>
       </ListView.ItemTemplate>
   </ListView>
   

Approach 3: Use WeakReferenceMessenger (For Loosely Coupled Scenarios) #

This is great if you don't want to pass data directly or use a shared ViewModel, and works well in .NET MAUI/Xamarin.Forms.

1. Define a message class:

public class CartUpdatedMessage
{
    public List<DATA> SelectedItems { get; set; }
}

2. Send the message from your main page:

var selectedItems = MainListView.SelectedItems.Cast<DATA>().ToList();
WeakReferenceMessenger.Default.Send(new CartUpdatedMessage { SelectedItems = selectedItems });

await Navigation.PushAsync(new CheckoutPage());

3. Receive the message in your checkout page:

using CommunityToolkit.Mvvm.Messaging;

public partial class CheckoutPage : ContentPage
{
    public CheckoutPage()
    {
        InitializeComponent();
        
        // Register to receive the cart update message
        WeakReferenceMessenger.Default.Register<CartUpdatedMessage>(this, (recipient, message) =>
        {
            CheckoutListView.ItemsSource = message.SelectedItems;
        });
    }

    // Unregister to prevent memory leaks when the page is dismissed
    protected override void OnDisappearing()
    {
        base.OnDisappearing();
        WeakReferenceMessenger.Default.Unregister<CartUpdatedMessage>(this);
    }
}

Quick Note: Ensure Multi-Selection is Enabled #

Don't forget to set your main ListView's SelectionMode to Multiple if you want users to select more than one item:

<ListView x:Name="MainListView" SelectionMode="Multiple">
    <!-- Your item template here -->
</ListView>

内容的提问来源于stack exchange，提问作者Mike M