Child elements of scrollviewer preventing scrolling with mouse wheel?

Question

I\'m having a problem getting mouse wheel scrolling to work in the following XAML, which I have simplified for clarity:

Answer 1

I know it's a little late but I have another solution that worked for me. I switched out my stackpanel/listbox for an itemscontrol/grid. Not sure why the scroll events work properly but they do in my case.

<ScrollViewer VerticalScrollBarVisibility="Auto" PreviewMouseWheel="ScrollViewer_PreviewMouseWheel">
                <StackPanel Orientation="Vertical">
                    <ListBox ItemsSource="{Binding DrillingConfigs}" Margin="0,5,0,0">
                        <ListBox.ItemTemplate>
                            <DataTemplate>

became

<ScrollViewer VerticalScrollBarVisibility="Auto" PreviewMouseWheel="ScrollViewer_PreviewMouseWheel">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="*" />
            <RowDefinition Height="Auto" />
        </Grid.RowDefinitions>
        <ItemsControl ItemsSource="{Binding DrillingConfigs}" Margin="0,5,0,0" Grid.Row="0">
            <ItemsControl.ItemTemplate>
                <DataTemplate>

Answer 2

Another way of implementing this, is by creating you own ScrollViewer like this:

public class MyScrollViewer : ScrollViewer
{
    protected override void OnMouseWheel(MouseWheelEventArgs e)
    {
        var parentElement = Parent as UIElement;
        if (parentElement != null)
        {
            if ((e.Delta > 0 && VerticalOffset == 0) ||
                (e.Delta < 0 && VerticalOffset == ScrollableHeight))
            {
                e.Handled = true;

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

        base.OnMouseWheel(e);
    }
}

Answer 3

You can also create a behavior and attach it to the parent control (in which the scroll events should bubble through).

// Used on sub-controls of an expander to bubble the mouse wheel scroll event up 
public sealed class BubbleScrollEvent : 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);
    }
}

<SomePanel>
            <i:Interaction.Behaviors>
                <viewsCommon:BubbleScrollEvent />
            </i:Interaction.Behaviors>
</SomePanel>

Answer 4

Specifying a ControlTemplate for the Listbox which doesn't include a ScrollViewer solves the problem. See this answer and these two MSDN pages for more information:

ControlTemplate

ListBox Styles and Templates