ListBox, VirtualizingStackPanel, and Smooth Scrolling in WPF
Solution 1
When you uncheck CanContentScroll, you lose virtualization. And the answer is really frustrating: For now there is no out-of-the-box solution :(.
PS: This is not the first post here, asking this very question.
Solution 2
If you use .NET 4.5 (or 4.0 if you're willing to hack a bit) then there's an answer over here.
[Note that @Guilluame's comment was here way before this answer but it wasn't particularly visible when skimming for answers.]
Solution 3
For anyone searching at 2021 you can use solution like this:
You will keep scrolling and virtualization at the same time
<ItemsControl x:Name="TestIC" Grid.Row="1"
ScrollViewer.CanContentScroll="True"
VirtualizingPanel.IsVirtualizing="True"
VirtualizingPanel.VirtualizationMode="Recycling" >
<ItemsControl.ItemsPanel>
<ItemsPanelTemplate>
<VirtualizingStackPanel VirtualizingPanel.IsVirtualizing="True" VirtualizingPanel.VirtualizationMode="Recycling" />
</ItemsPanelTemplate>
</ItemsControl.ItemsPanel>
<ItemsControl.Template>
<ControlTemplate>
<Border
Padding="{TemplateBinding Control.Padding}"
Background="{TemplateBinding Panel.Background}"
BorderBrush="{TemplateBinding Border.BorderBrush}"
BorderThickness="{TemplateBinding Border.BorderThickness}"
SnapsToDevicePixels="True">
<ScrollViewer Padding="{TemplateBinding Control.Padding}" Focusable="False">
<ItemsPresenter SnapsToDevicePixels="{TemplateBinding UIElement.SnapsToDevicePixels}" />
</ScrollViewer>
</Border>
</ControlTemplate>
</ItemsControl.Template>
</ItemsControl>
Joel Cochran
Long time .NET and Azure developer currently focused on Data platform and process engineering. I lead the technology division for a data analytics and decision sciences firm. MSCIS, JM, ASPInsider. Former Microsoft MVP and Microsoft employee.
Updated on November 24, 2021Comments
-
Joel Cochran over 2 years
I have a
ListBox
that may have many rows of templated DB records, including anImage
, bound to anObservableCollection<MyItem>
. Sometimes the collection could hold thousands of items.The performance is great, but the scrolling is the default jumpy behavior. I would like it to have smooth scrolling, so I unchecked
ScrollViewer.CanContentScroll
.Now I have smooth scrolling, but the performance is horrendous: the data is retrieved in a separate thread, and the thread finishes quickly, but it takes 10-20 seconds for the results to show in the
ListBox
. I assume that this is because uncheckingScrollViewer.CanContentScroll
changes the underlyingVirtualizingStackPanel
to a regularStackPanel
and so it is loading the entire collection before displaying the results.So my question is this: how do I retain the the smooth scrolling without sacrificing the
VirtualizingStackPanel
behavior and performance? -
Joel Cochran over 14 yearsI was afraid of that but had to ask. I searched before asking but didn't find that post. I might dig just a little bit more, but time is limited so I'll have to lose Smooth Scrolling for now.