ListBox, VirtualizingStackPanel, and Smooth Scrolling in WPF
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20-09-2019 - |
Question
I have a ListBox
that may have many rows of templated DB records, including an Image
, bound to an ObservableCollection<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 unchecking ScrollViewer.CanContentScroll
changes the underlying VirtualizingStackPanel
to a regular StackPanel
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?
Solution
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.
OTHER TIPS
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.]