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原标题:Bubbling scroll events from a ListView to its parent
  • 时间:2009-10-18 17:16:01
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在我提出的WPF申请中,有一个<代码>ListView,其<编码>ScrollViewer.VerticalScroll BarVisibility被设定为Disabled。 载于<编码>。 当我试图在<代码>ListView上使用 mo轮时,外部<代码>ScrollerView不会滚动,因为<代码>ListView正在捕获滚动活动。

我怎么能够把<条码>ListView强加于人,使滚动活动到<条码>上ub。 ScrollViewer

最佳回答

你们需要在内部清单调查中记录预估会活动。

MyListView.PreviewMouseWheel += HandlePreviewMouseWheel;

或者在XAML中

<ListView ... PreviewMouseWheel="HandlePreviewMouseWheel">

然后,从登记表上停止活动,并在括号中提出活动。

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);
    }
}

数月前,Creds去@robert-wagner为我解决了这个问题。

问题回答

Another nice solution using attached behavior. I like it because it decoples the solution from the Control.

创造一种不松散的行为,以追捕PreviewMouseWheel(Tunneling)活动,并提出新的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,将行为附在任何UIElement 案,并附上了“SrollViewers”案。

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

http://josheinstein.com/blog/index.php/201008/wpf-nested-scrollviewer-list Box-scrolling/>。 Amnesty Einstein Blog

如果你再次来到这里,就寻找解决办法,解决儿童处于顶端、roll上或下游和roll下的生活,这里就是一个解决办法。 我只用数据Grid测试了这一结果,但也应与其他控制合作。

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;
    }
}

随函附上以下文体和XAML号:

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

    <i:Interaction.Behaviors>
        <shared:ScrollParentWhenAtMax />
    </i:Interaction.Behaviors>

视你的具体情况,有不同的办法,但我发现,这样做是 n的。 假设你的基本情况是:

<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>

D. 提高摩擦 轮式 PreviewMouse 轮班似乎强迫SchrollViewer工作。 我希望我知道,为什么这似乎非常令人信服。

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);
}

你们也可以用所附的行为来做同样的事。 这样做的好处是不需要该系统。 视窗。 互动图书馆。 逻辑是从其他答复中得出的,只有执行不同。

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);
        }
    }
}

之后,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>

强化关键

我将你的回答作为RX延伸方法

    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);
               }
           });
    }

使用:

 myList.ScrollsParent().DisposeWith(disposables);

My use case was slightly different. I have a very big scrollviewer and at the bottom another scrollviewer which has a maxheight of 600. I want to scroll the whole page to the bottom until I pass scrollevents to the inner scrollviewer. This ensures you see the whole scrollviewer first, before you start scrolling.

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;
    }
}
}

奥基是自我执政以来的一个时期,但我不得不就此发表意见。 任何审查活动隧道,我们为什么要放弃吗? 停止在母体内的隧道,并与之做成。 括号中增加了一项PreviewMouseWheel活动。

     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;
}




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