WPF中如何让ListView SelectionChanged在MouseUp触发且支持多选

• 需求：修改WPF ListView（继承自Selector）默认交互逻辑，让SelectionChanged事件从默认的鼠标按下（MouseDown）触发，改为鼠标松开（MouseUp）触发
• 改造原因：默认逻辑下鼠标按下就会切换选中项，会干扰MouseMove事件中绑定的对象拖拽功能
• 现有方案缺陷：找到的附加属性实现仅支持单项选中，无法兼容Ctrl点选、Shift范围选的多选场景，还会拦截表头点击、滚动条拖动等原有交互

原实现的核心问题是直接在MouseUp事件中硬编码设置SelectedIndex，完全忽略了键盘修饰键状态、选择模式差异，且无差别拦截所有左键点击事件破坏了控件其他交互。以下是修复后的完整代码：

public static class SelectorBehavior
{
    #region ShouldSelectItemOnMouseUp 附加属性
    public static readonly DependencyProperty ShouldSelectItemOnMouseUpProperty =
        DependencyProperty.RegisterAttached(
            "ShouldSelectItemOnMouseUp", typeof(bool), typeof(SelectorBehavior),
            new PropertyMetadata(default(bool), OnShouldSelectItemOnMouseUpChanged));

    public static void SetShouldSelectItemOnMouseUp(DependencyObject element, bool value)
        => element.SetValue(ShouldSelectItemOnMouseUpProperty, value);

    public static bool GetShouldSelectItemOnMouseUp(DependencyObject element)
        => (bool)element.GetValue(ShouldSelectItemOnMouseUpProperty);

    // 缓存上一次选中项索引，用于Shift范围选择
    private static readonly DependencyProperty LastSelectedIndexProperty =
        DependencyProperty.RegisterAttached("LastSelectedIndex", typeof(int?), 
            typeof(SelectorBehavior), new PropertyMetadata(null));
    private static void SetLastSelectedIndex(DependencyObject element, int? value) 
        => element.SetValue(LastSelectedIndexProperty, value);
    private static int? GetLastSelectedIndex(DependencyObject element) 
        => (int?)element.GetValue(LastSelectedIndexProperty);

    private static void OnShouldSelectItemOnMouseUpChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        if (d is not Selector selector) return;
        
        selector.PreviewMouseLeftButtonDown -= OnPreviewMouseLeftButtonDown;
        selector.PreviewMouseLeftButtonUp -= OnPreviewMouseLeftButtonUp;

        if ((bool)e.NewValue)
        {
            selector.PreviewMouseLeftButtonDown += OnPreviewMouseLeftButtonDown;
            selector.PreviewMouseLeftButtonUp += OnPreviewMouseLeftButtonUp;
        }
    }

    private static void OnPreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
    {
        var selector = (Selector)sender;
        if (e.OriginalSource is not DependencyObject source) return;
        // 仅拦截点击在列表项上的事件，不拦截表头、滚动条、空白区域点击
        var container = selector.ContainerFromElement(source) as ListViewItem;
        if (container == null) return;
        
        // 拦截默认MouseDown选中逻辑，将选中时机延后到MouseUp
        e.Handled = true;
        // 捕获鼠标，保证鼠标拖动到项外松开也能正常触发事件
        container.CaptureMouse();
    }

    private static void OnPreviewMouseLeftButtonUp(object sender, MouseButtonEventArgs e)
    {
        var selector = (Selector)sender;
        if (e.OriginalSource is not DependencyObject source)
        {
            Mouse.Capture(null);
            return;
        }
        
        var container = selector.ContainerFromElement(source) as ListViewItem;
        if (container == null)
        {
            Mouse.Capture(null);
            return;
        }
        
        container.ReleaseMouseCapture();
        var currentIndex = selector.ItemContainerGenerator.IndexFromContainer(container);
        if (currentIndex < 0) return;

        var keyboardMods = Keyboard.Modifiers;
        // 对应不同选择模式执行和原生一致的选中逻辑
        switch (selector.SelectionMode)
        {
            case SelectionMode.Single:
                selector.SelectedIndex = currentIndex;
                break;
            case SelectionMode.Multiple:
                container.IsSelected = !container.IsSelected;
                break;
            case SelectionMode.Extended:
                if (keyboardMods.HasFlag(ModifierKeys.Control))
                {
                    // Ctrl点击：切换当前项选中状态，保留其他已选项
                    container.IsSelected = !container.IsSelected;
                }
                else if (keyboardMods.HasFlag(ModifierKeys.Shift))
                {
                    // Shift点击：选中上次选中项到当前项的全部范围
                    var lastIndex = GetLastSelectedIndex(selector) ?? selector.SelectedIndex;
                    if (lastIndex >= 0)
                    {
                        selector.UnselectAll();
                        int start = Math.Min(lastIndex.Value, currentIndex);
                        int end = Math.Max(lastIndex.Value, currentIndex);
                        for (int i = start; i <= end; i++)
                        {
                            if (selector.ItemContainerGenerator.ContainerFromIndex(i) is ListViewItem item)
                                item.IsSelected = true;
                        }
                    }
                    else
                    {
                        selector.SelectedIndex = currentIndex;
                    }
                }
                else
                {
                    // 普通点击：清空其他选中，仅选当前项
                    selector.UnselectAll();
                    container.IsSelected = true;
                }
                break;
        }

        SetLastSelectedIndex(selector, currentIndex);
        e.Handled = true;
    }
    #endregion
}

• 直接用上述代码替换项目中原有的SelectorBehavior类即可，现有XAML中配置的local:SelectorBehavior.ShouldSelectItemOnMouseUp="True"不需要修改
• 完整兼容ListView三种SelectionMode，支持Ctrl点选、Shift范围选的系统标准多选交互
• 修复了原实现拦截表头点击、滚动条拖动的问题，不影响GridView列排序、滚动条操作、进度条悬浮提示等原有功能
• 鼠标按下后拖动过程不会触发选中，和拖拽逻辑完全兼容：在MouseMove事件中判断鼠标按下且移动距离达到拖拽阈值时启动拖拽即可，不会出现按下就切换选中项干扰拖拽的问题

内容的提问来源于stack exchange，提问作者Siegfried.V