WinUI 3+C#：如何绑定ListView多选自动生成的CheckBox？

当WinUI 3的ListView设置SelectionMode="Multiple"时，自动生成的复选框属于ListViewItem内部控件，无法直接绑定自定义数据对象的IsSelected属性，下面提供两种可行的实现方式：

方案一：通过修改ListViewItem样式实现绑定 #

自定义ListViewItem的模板，将自动生成的复选框状态与数据项的IsSelected属性双向绑定：

1. 在页面资源中定义自定义ListViewItem样式：

<Page.Resources>
    <Style x:Key="CustomListViewItemStyle" TargetType="ListViewItem">
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="ListViewItem">
                    <ListViewItemPresenter 
                        CheckBoxBrush="{ThemeResource SystemControlForegroundBaseHighBrush}"
                        ContentMargin="{TemplateBinding Padding}"
                        <!-- 核心绑定：将复选框状态与数据项IsSelected双向绑定 -->
                        CheckBoxIsChecked="{Binding IsSelected, Mode=TwoWay}"
                        ContentTransitions="{TemplateBinding ContentTransitions}"
                        CheckMode="Inline"
                        DragOpacity="{ThemeResource ListViewItemDragThemeOpacity}"
                        DisabledOpacity="{ThemeResource ListViewItemDisabledThemeOpacity}"
                        DragBackground="{ThemeResource ListViewItemDragBackground}"
                        DragForeground="{ThemeResource ListViewItemDragForeground}"
                        FocusBorderBrush="{ThemeResource SystemControlForegroundAltHighBrush}"
                        FocusSecondaryBorderBrush="{ThemeResource SystemControlForegroundBaseHighBrush}"
                        HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}"
                        PointerOverBackground="{ThemeResource ListViewItemPointerOverBackground}"
                        PointerOverForeground="{ThemeResource ListViewItemPointerOverForeground}"
                        PressedBackground="{ThemeResource ListViewItemPressedBackground}"
                        ReorderHintOffset="{ThemeResource ListViewItemReorderHintThemeOffset}"
                        SelectedBackground="{ThemeResource ListViewItemSelectedBackground}"
                        SelectedForeground="{ThemeResource ListViewItemSelectedForeground}"
                        SelectedPointerOverBackground="{ThemeResource ListViewItemSelectedPointerOverBackground}"
                        SelectedPressedBackground="{ThemeResource ListViewItemSelectedPressedBackground}"
                        VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"/>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
</Page.Resources>

2. 修改ListView的ItemContainerStyle引用自定义样式：

<ListView x:Name="filterListView" SelectionMode="Multiple"
          ItemContainerStyle="{StaticResource CustomListViewItemStyle}">
    <ListView.ItemTemplate>
        <DataTemplate>
            <TextBlock Text="{Binding SubFilterName}" TextWrapping="Wrap" />
        </DataTemplate>
    </ListView.ItemTemplate>
</ListView>

方案二：通过C#后台事件同步选中状态 #

如果不想修改样式，可以通过监听ListView的选择事件和数据项的属性变化事件，实现双向状态同步：

1. 确保数据项实现INotifyPropertyChanged接口：

public class SubFilter : INotifyPropertyChanged
{
    private string _subFilterName;
    private bool _isSelected;

    public string SubFilterName
    {
        get => _subFilterName;
        set
        {
            _subFilterName = value;
            OnPropertyChanged(nameof(SubFilterName));
        }
    }

    public bool IsSelected
    {
        get => _isSelected;
        set
        {
            _isSelected = value;
            OnPropertyChanged(nameof(IsSelected));
        }
    }

    public event PropertyChangedEventHandler PropertyChanged;

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

2. 后台代码绑定事件并同步状态：

public MainPage()
{
    InitializeComponent();

    // 初始化示例数据
    var subFilters = new ObservableCollection<SubFilter>
    {
        new SubFilter { SubFilterName = "筛选项1", IsSelected = false },
        new SubFilter { SubFilterName = "筛选项2", IsSelected = true },
        new SubFilter { SubFilterName = "筛选项3", IsSelected = false }
    };

    filterListView.ItemsSource = subFilters;

    // 监听ListView选择变化，同步到数据项IsSelected
    filterListView.SelectionChanged += FilterListView_SelectionChanged;

    // 监听数据项属性变化，同步到ListView选中状态
    foreach (var item in subFilters)
    {
        item.PropertyChanged += SubFilter_PropertyChanged;
    }
}

private void FilterListView_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
    foreach (SubFilter addedItem in e.AddedItems)
    {
        if (addedItem.IsSelected != true) addedItem.IsSelected = true;
    }

    foreach (SubFilter removedItem in e.RemovedItems)
    {
        if (removedItem.IsSelected != false) removedItem.IsSelected = false;
    }
}

private void SubFilter_PropertyChanged(object sender, PropertyChangedEventArgs e)
{
    if (e.PropertyName != nameof(SubFilter.IsSelected)) return;

    var item = sender as SubFilter;
    if (item == null) return;

    if (item.IsSelected && !filterListView.SelectedItems.Contains(item))
    {
        filterListView.SelectedItems.Add(item);
    }
    else if (!item.IsSelected && filterListView.SelectedItems.Contains(item))
    {
        filterListView.SelectedItems.Remove(item);
    }
}

内容的提问来源于stack exchange，提问作者Ethan Allen