The FillSceneGraph event replaces the need to create a custom layer class. Instead of implementing an ILayer interface, you can simply handle the chart’s FillSceneGraph event and modify the scene graph directly.
The FillSceneGraphEventArgs object, which is passed in to the FillSceneGraph event, exposes several important members of ChartCore, such as Grid Hashtable, SceneGraph and the ChartCore itself.
The FillSceneGraph event is used to add/remove Primitives to/from your chart before the chart is rendered.
The following screen shot displays a column chart with a custom text string. The string "Sample Text" was added by using a Text primitive.