将Tuple中bool值绑定到ListBox模板CheckBox致程序崩溃

你的问题核心出在Tuple的不可变性上！Tuple的Item2和Item3是只读属性（只有get访问器，没有set），而WPF中CheckBox.IsChecked的绑定默认是双向绑定（Mode=TwoWay）。当用户点击CheckBox时，WPF会尝试修改绑定的属性值，但Tuple的Item无法被修改，直接抛出异常导致程序崩溃。

解决步骤： #

1. 创建自定义的用户选择ViewModel类

替换不可变的Tuple，用一个实现INotifyPropertyChanged的类来承载数据，这样既支持属性修改，又能通知UI更新：

public class UserSelectionViewModel : INotifyPropertyChanged
{
    private UserDetails _userDetails;
    private bool _isWriteSelected;
    private bool _isManageSelected;

    public UserDetails UserDetails
    {
        get => _userDetails;
        set
        {
            _userDetails = value;
            OnPropertyChanged(nameof(UserDetails));
        }
    }

    public bool IsWriteSelected
    {
        get => _isWriteSelected;
        set
        {
            _isWriteSelected = value;
            OnPropertyChanged(nameof(IsWriteSelected));
        }
    }

    public bool IsManageSelected
    {
        get => _isManageSelected;
        set
        {
            _isManageSelected = value;
            OnPropertyChanged(nameof(IsManageSelected));
        }
    }

    public event PropertyChangedEventHandler PropertyChanged;

    protected virtual void OnPropertyChanged(string propertyName)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
}

2. 更新你的集合类型与数据加载逻辑

把原来的ObservableCollection<Tuple<UserDetails, bool, bool>>换成自定义类的集合，并修改GetUsers方法：

private ObservableCollection<UserSelectionViewModel> _users;
public ObservableCollection<UserSelectionViewModel> Users { 
    get { return _users; } 
    set { _users = value; OnPropertyRaised("Users"); } 
}

public async Task GetUsers() {
    var tmp = await watchlistHelper.GetUsersAsync();
    if (tmp != null) {
        Users = new ObservableCollection<UserSelectionViewModel>();
        foreach (UserDetails details in tmp.Content) {
            Users.Add(new UserSelectionViewModel
            {
                UserDetails = details,
                IsWriteSelected = false,
                IsManageSelected = false
            });
        }
    }
}

3. 修改XAML绑定路径

现在绑定到自定义类的属性，而不是Tuple的Item：

<ListBox Grid.Column="2" Grid.Row="1" ItemsSource="{Binding Users, ElementName=uc}" HorizontalContentAlignment="Stretch" SelectionMode="Multiple">
    <ListBox.ItemTemplate >
        <DataTemplate>
            <Grid>
                <Grid.ColumnDefinitions>
                    <ColumnDefinition Width="*"/>
                    <ColumnDefinition SharedSizeGroup="write"/>
                    <ColumnDefinition SharedSizeGroup="manage"/>
                </Grid.ColumnDefinitions>
                <TextBlock Margin="2" Text="{Binding UserDetails.UserName}" VerticalAlignment="Center"/>
                <CheckBox Margin="2" IsChecked="{Binding IsWriteSelected}" HorizontalAlignment="Center" VerticalAlignment="Center" Grid.Column="1"/>
                <CheckBox Margin="2" IsChecked="{Binding IsManageSelected}" HorizontalAlignment="Center" VerticalAlignment="Center" Grid.Column="2"/>
            </Grid>
        </DataTemplate>
    </ListBox.ItemTemplate>
</ListBox>

为什么这样能解决问题？ #

自定义类的属性有完整的get和set访问器，并且实现了INotifyPropertyChanged，既支持双向绑定的修改操作，又能在属性值变化时通知UI更新，完美适配WPF的数据绑定机制。

内容的提问来源于stack exchange，提问作者Simas Paškauskas