Multi-touch ScrollViewer eating touch events

Question

WPF 4.0:

I have scroll viewer with many Sliders inside of it. I want the scroll viewer to pan with touch, and I want the internal slider to also respond to touch.

Unfortunately, the scroll viewer is eating the "TouchMove" events and not passing them down to the slider control. Any idea how to fix this?

Here is my XAML:

<Window x:Class="ScrollingTest.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525">
    <Grid>
        <ItemsControl ItemsSource="{Binding}">
            <ItemsControl.Template>
                <ControlTemplate>
                    <ScrollViewer VerticalScrollBarVisibility="Auto" PanningMode="Both" >
                        <ItemsPresenter />
                    </ScrollViewer>
                </ControlTemplate>
            </ItemsControl.Template>
            <ItemsControl.ItemTemplate>
                <DataTemplate>
                    <Border Height="100" BorderThickness="2" BorderBrush="Black">
                        <Slider Value="{Binding ., Mode=TwoWay}" Width="300" Minimum="0" Maximum="100" />
                    </Border>
                </DataTemplate>
            </ItemsControl.ItemTemplate>
        </ItemsControl>
    </Grid>
</Window>

And my Code-behind:

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
        DataContext = Items;
    }

    public IEnumerable<int> Items
    {
        get
        {
            return Enumerable.Range(0, 50);
        }
    }
}

Answer 1

Hey Brian,

This sounds like a case of "routed event marked as handled". Can you try using AddHandler to subscribe to that event, and set the last parameter "handledEventsToo" to true?

Cheers, Laurent

Answer 2

It's handling the TouchMove event, most likely. There are bubbling events (PreviewTouchMove, etc) you could handle in your Slider control. You would need to coordinate how you want the touch events to be handled.