65

在我的 WPF 应用程序中，我将ListView其ScrollViewer.VerticalScrollBarVisibility设置为Disabled. 它包含在一个ScrollViewer. 当我尝试在 上使用鼠标滚轮时ListView，外部ScrollViewer不会滚动，因为ListView正在捕获滚动事件。

如何强制ListView允许滚动事件冒泡到ScrollViewer？

4

8 回答 8

99

您需要在内部列表视图中捕获预览鼠标滚轮事件

MyListView.PreviewMouseWheel += HandlePreviewMouseWheel;

或在 XAML 中

<ListView ... PreviewMouseWheel="HandlePreviewMouseWheel">

然后停止滚动列表视图的事件并在父列表视图中引发事件。

private void HandlePreviewMouseWheel(object sender, MouseWheelEventArgs e) {
    if (!e.Handled) {
        e.Handled = true;
        var eventArg = new MouseWheelEventArgs(e.MouseDevice, e.Timestamp, e.Delta);
        eventArg.RoutedEvent = UIElement.MouseWheelEvent;
        eventArg.Source = sender;
        var parent = ((Control)sender).Parent as UIElement;
        parent.RaiseEvent(eventArg);
    }
}

信誉转到几个月前为我解决了这个问题的@robert-wagner。

于 2010-12-03T05:29:37.817 回答
43

使用附加行为的另一个不错的解决方案。我喜欢它，因为它从控制中解开了解决方案。

创建一个无滚动行为，它将捕获 PreviewMouseWheel(Tunneling) 事件并引发一个新的 MouseWheelEvent(Bubbling)

public sealed class IgnoreMouseWheelBehavior : Behavior<UIElement>
{

  protected override void OnAttached( )
  {
    base.OnAttached( );
    AssociatedObject.PreviewMouseWheel += AssociatedObject_PreviewMouseWheel ;
  }

protected override void OnDetaching( )
{
    AssociatedObject.PreviewMouseWheel -= AssociatedObject_PreviewMouseWheel;
    base.OnDetaching( );
}

void AssociatedObject_PreviewMouseWheel(object sender, MouseWheelEventArgs e)
{

    e.Handled = true;

    var e2 = new MouseWheelEventArgs(e.MouseDevice,e.Timestamp,e.Delta);
    e2.RoutedEvent = UIElement.MouseWheelEvent;
        AssociatedObject.RaiseEvent(e2);

    }
}

然后将行为附加到任何具有嵌套 ScrollViewers 案例的 UIElement

 <ListBox Name="ForwardScrolling">
    <i:Interaction.Behaviors>
        <local:IgnoreMouseWheelBehavior />
    </i:Interaction.Behaviors>
</ListBox>

全部归功于Josh Einstein 博客

于 2013-04-09T14:11:03.187 回答
11

如果您来这里寻找解决方案，仅当孩子位于顶部并向上滚动或底部并向下滚动时才冒泡事件，这里有一个解决方案。我只使用 DataGrid 对此进行了测试，但它也应该与其他控件一起使用。

public class ScrollParentWhenAtMax : Behavior<FrameworkElement>
{
    protected override void OnAttached()
    {
        base.OnAttached();
        this.AssociatedObject.PreviewMouseWheel += PreviewMouseWheel;
    }

    protected override void OnDetaching()
    {
        this.AssociatedObject.PreviewMouseWheel -= PreviewMouseWheel;
        base.OnDetaching();
    }

    private void PreviewMouseWheel(object sender, MouseWheelEventArgs e)
    {
        var scrollViewer = GetVisualChild<ScrollViewer>(this.AssociatedObject);
        var scrollPos = scrollViewer.ContentVerticalOffset;
        if ((scrollPos == scrollViewer.ScrollableHeight && e.Delta < 0)
            || (scrollPos == 0 && e.Delta > 0))
        {
            e.Handled = true;
            var e2 = new MouseWheelEventArgs(e.MouseDevice, e.Timestamp, e.Delta);
            e2.RoutedEvent = UIElement.MouseWheelEvent;
            AssociatedObject.RaiseEvent(e2);
        }
    }

    private static T GetVisualChild<T>(DependencyObject parent) where T : Visual
    {
        T child = default(T);

        int numVisuals = VisualTreeHelper.GetChildrenCount(parent);
        for (int i = 0; i < numVisuals; i++)
        {
            Visual v = (Visual)VisualTreeHelper.GetChild(parent, i);
            child = v as T;
            if (child == null)
            {
                child = GetVisualChild<T>(v);
            }
            if (child != null)
            {
                break;
            }
        }
        return child;
    }
}

要附加此行为，请将以下 XMLNS 和 XAML 添加到您的元素：

    xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"

    <i:Interaction.Behaviors>
        <shared:ScrollParentWhenAtMax />
    </i:Interaction.Behaviors>
于 2014-04-28T16:15:50.147 回答
4

根据您的具体情况，有不同的方法，但我发现这很好用。假设你的基本情况是这样的：

<Window Height="200" Width="200">
<Grid>
    <ScrollViewer Name="sViewer">
        <StackPanel>
            <Label Content="Scroll works here" Margin="10" />
            <ListView Name="listTest" Margin="10" 
                      PreviewMouseWheel="listTest_PreviewMouseWheel" 
                      ScrollViewer.VerticalScrollBarVisibility="Disabled">
                <ListView.ItemsSource>
                    <Int32Collection>
                        1,2,3,4,5,6,7,8,9,10
                    </Int32Collection>
                </ListView.ItemsSource>
                <ListView.View>
                    <GridView>
                        <GridViewColumn Header="Column 1" />
                    </GridView>
                </ListView.View>
            </ListView>
        </StackPanel>
    </ScrollViewer>
</Grid>
</Window>

在 PreviewMouseWheel 期间自己提高 MouseWheelEvent 似乎会强制 ScrollViewer 工作。我希望我知道为什么，这似乎很违反直觉。

private void listTest_PreviewMouseWheel(object sender, MouseWheelEventArgs e)
{
    e.Handled = true;
    MouseWheelEventArgs e2 = new MouseWheelEventArgs(e.MouseDevice, e.Timestamp, e.Delta);
    e2.RoutedEvent = UIElement.MouseWheelEvent;
    listTest.RaiseEvent(e2);
}
于 2010-08-20T19:02:59.670 回答
2

您也可以使用附加的行为来实现相同的目的。这具有不需要 System.Windows.Interactivity 库的优点。逻辑取自其他答案，只是实现方式不同。

public static class IgnoreScrollBehaviour
{
    public static readonly DependencyProperty IgnoreScrollProperty = DependencyProperty.RegisterAttached("IgnoreScroll", typeof(bool), typeof(IgnoreScrollBehaviour), new PropertyMetadata(OnIgnoreScollChanged));

    public static void SetIgnoreScroll(DependencyObject o, string value)
    {
        o.SetValue(IgnoreScrollProperty, value);
    }

    public static string GetIgnoreScroll(DependencyObject o)
    {
        return (string)o.GetValue(IgnoreScrollProperty);
    }

    private static void OnIgnoreScollChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        bool ignoreScoll = (bool)e.NewValue;
        UIElement element = d as UIElement;

        if (element == null)
            return;

        if (ignoreScoll)
        {
            element.PreviewMouseWheel += Element_PreviewMouseWheel;
        }
        else
        {
            element.PreviewMouseWheel -= Element_PreviewMouseWheel;
        }
    }

    private static void Element_PreviewMouseWheel(object sender, MouseWheelEventArgs e)
    {
        UIElement element = sender as UIElement;

        if (element != null)
        {
            e.Handled = true;

            var e2 = new MouseWheelEventArgs(e.MouseDevice, e.Timestamp, e.Delta);
            e2.RoutedEvent = UIElement.MouseWheelEvent;
            element.RaiseEvent(e2);
        }
    }
}

然后在 XAML 中：

<DataGrid ItemsSource="{Binding Items}">

<DataGrid.RowDetailsTemplate>
    <DataTemplate>

        <ListView ItemsSource="{Binding Results}"
                  behaviours:IgnoreScrollBehaviour.IgnoreScroll="True">
            <ListView.ItemTemplate>
                <DataTemplate>
                    ...
                </DataTemplate>
            </ListView.ItemTemplate>
        </ListView>
    </DataTemplate>
</DataGrid.RowDetailsTemplate>

<DataGrid.Columns>
   ...
</DataGrid.Columns>

</DataGrid>
于 2017-05-16T11:22:00.680 回答
1

谢谢凯尔

我将您的答案改编为 RX 扩展方法

    public static IDisposable ScrollsParent(this ItemsControl itemsControl)
    {
        return Observable.FromEventPattern<MouseWheelEventHandler, MouseWheelEventArgs>(
           x => itemsControl.PreviewMouseWheel += x,
           x => itemsControl.PreviewMouseWheel -= x)
           .Subscribe(e =>
           {
               if(!e.EventArgs.Handled)
               {
                   e.EventArgs.Handled = true;
                   var eventArg = new MouseWheelEventArgs(e.EventArgs.MouseDevice, e.EventArgs.Timestamp, e.EventArgs.Delta)
                   {
                       RoutedEvent = UIElement.MouseWheelEvent,
                       Source = e.Sender
                   };
                   var parent = ((Control)e.Sender).Parent as UIElement;
                   parent.RaiseEvent(eventArg);
               }
           });
    }

用法：

 myList.ScrollsParent().DisposeWith(disposables);
于 2019-06-23T14:28:37.443 回答
1

我的用例略有不同。我有一个非常大的滚动查看器，底部有另一个最大高度为 600 的滚动查看器。我想将整个页面滚动到底部，直到我将滚动事件传递给内部滚动查看器。这可以确保您在开始滚动之前首先看到整个滚动查看器。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Interactivity;
using System.Windows.Media;

namespace CleverScroller.Helper
{
public class ScrollParentWhenAtMax : Behavior<FrameworkElement>
{
    protected override void OnAttached()
    {
        base.OnAttached();
        this.AssociatedObject.PreviewMouseWheel += PreviewMouseWheel;
    }

    protected override void OnDetaching()
    {
        this.AssociatedObject.PreviewMouseWheel -= PreviewMouseWheel;
        base.OnDetaching();
    }

    private void PreviewMouseWheel(object sender, MouseWheelEventArgs e)
    {
        if (e.Delta < 0)
        {
            var outerscroller = GetVisualParent<ScrollViewer>(this.AssociatedObject);
            if (outerscroller.ContentVerticalOffset < outerscroller.ScrollableHeight)
            {
                e.Handled = true;
                var e2 = new MouseWheelEventArgs(e.MouseDevice, e.Timestamp, e.Delta);
                e2.RoutedEvent = UIElement.MouseWheelEvent;
                AssociatedObject.RaiseEvent(e2);
            }
        }
        else
        {
            var scrollViewer = GetVisualChild<ScrollViewer>(this.AssociatedObject);
            var scrollPos = scrollViewer.ContentVerticalOffset;
            if ((scrollPos == scrollViewer.ScrollableHeight && e.Delta < 0)
                || (scrollPos == 0 && e.Delta > 0))
            {
                e.Handled = true;
                var e2 = new MouseWheelEventArgs(e.MouseDevice, e.Timestamp, e.Delta);
                e2.RoutedEvent = UIElement.MouseWheelEvent;
                AssociatedObject.RaiseEvent(e2);
            }
        }
    }

    private static T GetVisualChild<T>(DependencyObject parent) where T : Visual
    {
        T child = default(T);

        int numVisuals = VisualTreeHelper.GetChildrenCount(parent);
        for (int i = 0; i < numVisuals; i++)
        {
            Visual v = (Visual)VisualTreeHelper.GetChild(parent, i);
            child = v as T;
            if (child == null)
            {
                child = GetVisualChild<T>(v);
            }
            if (child != null)
            {
                break;
            }
        }
        return child;
    }

    private static T GetVisualParent<T>(DependencyObject parent) where T : Visual
    {
        T obj = default(T);
        Visual v = (Visual)VisualTreeHelper.GetParent(parent);
        do
        {
            v = (Visual)VisualTreeHelper.GetParent(v);
            obj = v as T;
        } while (obj == null);

        return obj;
    }
}
}
于 2016-08-18T08:17:41.453 回答
0

好吧，自从我参加 SO 以来已经有一段时间了，但我不得不对此发表评论。任何预览事件隧道，那么我们为什么要冒泡呢？在父节点中停止隧道并完成它。在父级中添加一个 PreviewMouseWheel 事件。

     private void UIElement_OnPreviewMouseWheel(object sender, MouseWheelEventArgs e)
{
    var scrollViewer = FindName("LeftPanelScrollViwer"); // name your parent mine is a scrollViewer
    ((ScrollViewer) scrollViewer)?.ScrollToVerticalOffset(e.Delta);
    e.Handled = true;
}
于 2017-05-11T17:21:07.517 回答