XAML 页面中的 Bindable 值存在问题

我有一个保龄球回顾示例代码，其中输入了 3 场比赛并总结在系列列中。我遇到的问题是系列列没有按照我的预期进行更新。显然，我做错了什么，但看不到我做错了什么。以下是支持该应用程序的代码：

<?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="HoriView.MainPage">
    
    <StackLayout>
        <ScrollView>
            <VerticalStackLayout
                Spacing="25"
                Padding="30,0"
                VerticalOptions="Center">

                <Image
                    Source="dotnet_bot.png"
                    HeightRequest="200"
                    HorizontalOptions="Center" />
    
                <Label
                    Text="Hello, Bowlers!"
                    FontSize="32"
                    HorizontalOptions="Center" />
    
                <Label
                    Text="Bowling Recap Snippet"
                    FontSize="18"
                    HorizontalOptions="Center" />
    
            </VerticalStackLayout>
    
        </ScrollView>
        <ScrollView>
            <HorizontalStackLayout HorizontalOptions="Center">
                <CollectionView SelectionMode="Single" ItemsSource="{Binding scores}" ItemsLayout="HorizontalList">
                    <CollectionView.ItemTemplate>
                        <DataTemplate>
                            <Grid Padding="10">
                                <Grid.RowDefinitions>
                                    <RowDefinition Height="Auto"/>
                                    <RowDefinition Height="Auto"/>
                                    <RowDefinition Height="Auto"/>
                                    <RowDefinition Height="Auto"/>
                                </Grid.RowDefinitions>
                                <Grid.ColumnDefinitions>
                                    <ColumnDefinition Width="Auto"/>
                                </Grid.ColumnDefinitions>
                                <Label Text="{Binding Game}" FontSize="Medium" WidthRequest="83" VerticalOptions="Center" HorizontalOptions="EndAndExpand" HorizontalTextAlignment="End"></Label>
                               <Entry Grid.Row="1" Text="{Binding Score}" TextChanged="UpdateGame" Keyboard="Numeric" ReturnType="Next" Placeholder="Game" WidthRequest="83" FontSize="Medium" ></Entry>
                            </Grid>
                        </DataTemplate>
                    </CollectionView.ItemTemplate>
                </CollectionView>
            </HorizontalStackLayout>
        </ScrollView>
    </StackLayout>
    
</ContentPage>

using System.Collections.ObjectModel;
    
namespace HoriView;
    
public partial class MainPage : ContentPage
{
    public ObservableCollection<Games> scores { get; set; }
    string header = "Game";
    
    public MainPage()
    {
        InitializeComponent();
        scores= new ObservableCollection<Games>();
        for(int i=0; i<4; i++)
        {
            if (i == 3)
            {
                header = "Series";
            }
            else
            {
                header = "Game" + (i+1).ToString();
            }
            scores.Add(new Games() 
            { 
                Game=header, 
                Score=0
            });
                
        }
        BindingContext = this;
    }
    
    public void UpdateGame(object sender, TextChangedEventArgs e)
    {
        scores[scores.Count-1].Score = 0;
        for(int i=0; i< scores.Count-1; i++) 
        {
            scores[scores.Count - 1].Score += scores[i].Score;
        }
    }
}

public class Games
{
    public string Game { get; set; }
    public int Score { get; set; }
}

任何帮助，将不胜感激。谢谢。

Your Games类没有实现INotifyPropertyChanged界面。

您可以手动实现：

public class Games : INotifyPropertyChanged
{
    private string _game;
    public string Game
    {
        get => _game;
        set
        {
            if(_game == value) return;
            _game = value;
            OnPropertyChanged();
        }
    }

    private int _score;
    public int Score
    {
        get => _score;
        set
        {
            if(_score == value) return;
            _score = value;
            OnPropertyChanged();
        }
    }

    public event PropertyChangedEventHandler PropertyChanged;

    private void OnPropertyChanged([CallerMemberName] string propertyName = "")  
    {  
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }  
}

或者，您也可以继承自ObservableObject来自MVVM 社区工具包 https://learn.microsoft.com/dotnet/communitytoolkit/mvvm/然后使用源生成器简单地编写以下内容：

public partial class Games : ObservableObject
{
    [ObservableProperty]
    private string _game;

    [ObservableProperty]
    private int _score;
}

在这种情况下，您只需定义支持字段，源生成器将创建大写的可观察属性Game and Score为你。