///<summary>
/// Broadcast Unloaded event starting at this node
/// </summary>
internal void FireUnloadedOnDescendentsInternal()
{
// This is to prevent duplicate Broadcasts for the Unloaded event
if (UnloadedPending == null)
{
DependencyObject parent = Parent;
if (parent == null)
{
parent = VisualTreeHelper.GetParent(this);
}
// Check if this Unloaded cancels against a previously queued Loaded event
// Note that if the Loaded and the Unloaded do not change the position of
// the node within the loagical tree they are considered to cancel each other out.
object[] loadedPending = LoadedPending;
if (loadedPending == null)
{
// Add a callback to the MediaContext which will be called
// before the first render after this point
BroadcastEventHelper.AddUnloadedCallback(this, parent);
}
else
{
// Dequeue Loaded
BroadcastEventHelper.RemoveLoadedCallback(this, loadedPending);
}
}
}