private TraverseOptions InternalAdd(object descendant)
{
if (descendant == null)
{
throw new ArgumentNullException("descendant");
}
var collectionChanged = descendant as INotifyCollectionChanged <object>;
if (collectionChanged != null)
{
workingExpandables.Add(collectionChanged);
}
var queryable = descendant as ISpatialQueryable;
if (queryable != null)
{
// Choose the right scene manager for the target object
if (currentSceneManagerForAddition != null)
{
currentSceneManagerForAddition.Add(queryable);
}
else
{
defaultSceneManager.Add(queryable);
}
}
TrackObject(descendant);
OnAddedToScene(descendant);
var addedToScene = AddedToScene;
if (addedToScene != null)
{
addedToScene(descendant);
}
return(TraverseOptions.Continue);
}