c# - ScrollViewer mouse wheel not scrolling

Question

I am currently working on my first WPF project and trying to make a ListView scrollable. At first I thought this could be easily done by simply limiting the ListView's width and height and thus forcing a scrollbar to appear automatically whenever the content exceeds its space. This seemed fine at first but due to the handled PreviewMouseDown event (which enables dragging the list's items) it doesn't work after selecting an item.

Second attempt (using ScrollViewer)

<ScrollViewer>
    <ListView ItemsSource="{Binding FileViewModels}"
              PreviewMouseDown="ListView_MouseMove"
              Height="450" Width="200"/>
</ScrollViewer>

Of course, this resulted in a second scrollbar whenever the list's content became larger than its max height. And dragging the bar still didn't work after selecting an item.

Third (quite foolish) attempt (disabling scrollbar duplicate)

<ScrollViewer>
    <ListView ItemsSource="{Binding FileViewModels}"
              PreviewMouseDown="ListView_MouseMove"
              Height="450" Width="200"
              ScrollViewer.VerticalScrollBarVisibility="Disabled"
              ScrollViewer.HorizontalScrollBarVisibility="Disabled"/>
</ScrollViewer>

This removed the scrollbar duplicate and enabled scrolling via mouse wheel but disabled the scrollbar, so you couldn't move by clicking and dragging it.

Fourth attempt (constant size of the ScrollViewer)

<ScrollViewer Height="450" Width="200">
    <ListView ItemsSource="{Binding FileViewModels}"
              PreviewMouseDown="ListView_MouseMove"/>
</ScrollViewer>

Removed the width/height constraint from the ListView and moved it to the ScrollViewer. This enables the scrollbar and removes the duplicate. Unfortunately the mouse wheel doesn't work anymore (dragging the scroll bar works fine).

Could somebody please explain to me why the mouse wheel doesn't work anymore and how to fix this?

Edit Maybe I should go back to my first solution.

Obviously, the ListView's template already contains a ScrollViewer. The remaining problem would then be that I cannot drag the scrollbar after selecting an item because of the handled PreviewMouseDown event (scrolling via MouseWheel still works in that case). Should I handle the dragging of items differently (it worked fine for me, before wanting to add a scrollbar)? Or is there a way to detect if the cursor is above the scrollbar (so I could then deselect the item which enables scrolling)? Or are there any other suggestions?

Answer 1

This may help you..

private void ListViewScrollViewer_PreviewMouseWheel(object sender, System.Windows.Input.MouseWheelEventArgs e)
{
   ScrollViewer scv = (ScrollViewer)sender;
   scv.ScrollToVerticalOffset(scv.VerticalOffset - e.Delta);
   e.Handled = true;
 }