Occurs just before the objects in the composition tree are rendered.
Assembly: PresentationCore (in PresentationCore.dll)
XMLNS for XAML: http://schemas.microsoft.com/winfx/2006/xaml/presentation, http://schemas.microsoft.com/netfx/2007/xaml/presentation
The event is raised during the Windows Presentation Foundation (WPF) rendering process. The following example shows how you register an EventHandler delegate to the static method on CompositionTarget.
You can use your rendering event handler to create custom drawing content. This event handler gets called once per frame. Each time that Windows Presentation Foundation (WPF) marshals the persisted rendering data in the visual tree across to the composition tree, your event handler is called. In addition, if changes to the visual tree force updates to the composition tree, your event handler is also called. Note that your event handler is called after layout has been computed. However, you can modify layout in your event handler, which means that layout will be computed once more before rendering.