ListBox, VirtualizingStackPanel, and Smooth Scrolling in WPF

Joel Cochran picture Joel Cochran · Dec 17, 2009 · Viewed 20.6k times · Source

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?

Answer

Anvaka picture Anvaka · Dec 17, 2009

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.