Top 11 WPF Performance Tips

Windows Presentation Foundation provides a very confortable way to develop rich user experiences. A drop shadow for example can added by inserting two simple lines of XML. But this simplicity can also mislead us to overuse them. This leads to performance issues. The following tipps may help you to avoid or fix them.

1. Dispatch expensive calls either within the UI thread with a lower DispatcherPriority by calling Dispatcher.BeginInvoke() or to a background thread by using a BackgroundWorker to keep the UI responsive.
2. Fix binding errors because they consume a lot of time, trying to resolve the path error, including searching for attached properties. You can find them by looking for System.Windows.Data Error in the Visual Studio output log.
3. Reduce the number of visuals by removing unneeded elements, combining layout panels and simplifying templates. This keeps the memory footprint small and improves the rendering performance.
4. Prevent Software Rendering. The use of transparent windows by setting AllowsTransparency to true or using old BitmapEffects can cause WPF to render the UI in software on Windows XP, which is much slower.
5. Load resources when needed. Even thow it's the most comfortable way to merge all resources on application level it can also cost performance by loading all resources at startup. A better approach is to load only often used resources and load the other on view level.
6. Virtualize lists and views by using a VirtualizingStackPanel as ItemsPanel for lists. This only creates the visible elements at load time. All other elements are lazy created when they get visible. Be aware that grouping or CanContextScrol="True" prevents virtualization!
7. Enable Container Recycling. Virtualization brings a lot of performance improvements, but the containers will be disposed and re created, this is the default. But you can gain more performance by recycle containers by setting VirtualizingStackPanel.VirtualizationMode="Recycling"
8. Freeze Freezables by calling Freeze() in code or PresentationOptions:Freeze="true" in XAML. This reduces memory consumption and improves performance, because the system don't need to monitor for changes.
9. Disable Assembly localization if you don't need it. By using the [NeutralResourcesLanguageAttribute]. This prevents an expensive lookup for satelite assemblies
10. Lower the framerate of animations by setting Storyboard.DesiredFrameRate to lower the CPU load. The default is 60 frames/second
11. Use StreamGeometries instead of PathGeometries if possible to draw complex 2D geometries, because they are much more efficient and consume less memory.

Other articles about WPF performance

• Improve application startup performance (Jossef Goldberg)

WPF Performance Tools

There are two interesting tools to trace your WPF application and narrow down performance leaks:

• Snoop to check the number of visuals.
• WPF Performance Suite to trace events and rendering time