The scroller does not scroll inside the listbox inside the itemscontrol-CodePudding

I made the following code to illustrate the problem, The goal is to be able to scroll when the mouse is on the Listbox

public List<List<string>> StringList { get; set; } = new() { new() { "A", "B", "C", "D" }, new() { "A", "B", "C", "D" } };


<Grid>
    <ScrollViewer MaxHeight="100">
        <ItemsControl ItemsSource="{Binding Path=StringList}">
            <ItemsControl.ItemTemplate>
                <DataTemplate>
                    <Grid>
                        <ListBox ItemsSource="{Binding}">
                            <ListBox.ItemTemplate>
                                <DataTemplate>
                                    <TextBox Text="{Binding Path=.}"/>
                                </DataTemplate>
                            </ListBox.ItemTemplate>
                        </ListBox>
                    </Grid>
                </DataTemplate>
            </ItemsControl.ItemTemplate>
        </ItemsControl>
    </ScrollViewer>
</Grid>

CodePudding user response：

If you want to be able to scroll the outer ScrollViewer (ItemsControl) using the mouse wheel, you could handle the PreviewMouseWheel event for the inner ListBox like this:

private void ListBox_PreviewMouseWheel(object sender, MouseWheelEventArgs e)
{
    if (sender is ListBox && !e.Handled)
    {
        e.Handled = true;
        UIElement parent = ((Control)sender).Parent as UIElement;
        parent?.RaiseEvent(new MouseWheelEventArgs(e.MouseDevice, e.Timestamp, e.Delta)
        {
            RoutedEvent = UIElement.MouseWheelEvent,
            Source = sender
        });
    }
}

XAML:

<ScrollViewer MaxHeight="100" VerticalScrollBarVisibility="Auto" HorizontalScrollBarVisibility="Auto">
    <ItemsControl ItemsSource="{Binding Path=StringList}">
        <ItemsControl.ItemTemplate>
            <DataTemplate>
                <Grid>
                    <ListBox ItemsSource="{Binding}" PreviewMouseWheel="ListBox_PreviewMouseWheel">
                        <ListBox.ItemTemplate>
                            <DataTemplate>
                                <TextBox Text="{Binding Path=.}"/>
                            </DataTemplate>
                        </ListBox.ItemTemplate>
                    </ListBox>
                </Grid>
            </DataTemplate>
        </ItemsControl.ItemTemplate>
    </ItemsControl>
</ScrollViewer>