// Callback on visiting each node in the descendency during a broadcast event
private static bool OnBroadcastCallback(DependencyObject d, BroadcastEventData data, bool visitedViaVisualTree)
{
DependencyObject root = data.Root;
RoutedEvent routedEvent = data.RoutedEvent;
List<DependencyObject> eventRoute = data.EventRoute;
if (FrameworkElement.DType.IsInstanceOfType(d))
{
// If this is a FrameworkElement
FrameworkElement fe = (FrameworkElement)d;
if (fe != root && routedEvent == FrameworkElement.LoadedEvent && fe.UnloadedPending != null)
{
// If there is a pending Unloaded event wait till we've broadcast
// that event before we can fire the new Loaded event.
fe.FireLoadedOnDescendentsInternal();
}
else if (fe != root && routedEvent == FrameworkElement.UnloadedEvent && fe.LoadedPending != null)
{
// If there is a pending Loaded event abort it because we are now
// being Unloaded.
RemoveLoadedCallback(fe, fe.LoadedPending);
}
else
{
if (fe != root)
{
if (routedEvent == FrameworkElement.LoadedEvent && fe.LoadedPending != null)
{
// If there is a pending Loaded event abort it because we are now
// being Loaded.
RemoveLoadedCallback(fe, fe.LoadedPending);
}
else if (routedEvent == FrameworkElement.UnloadedEvent && fe.UnloadedPending != null)
{
// If there is a pending Unloaded event abort it because we are now
// being Unloaded.
RemoveUnloadedCallback(fe, fe.UnloadedPending);
}
}
// If element has handlers fire the event and continue to walk down the tree
if (fe.SubtreeHasLoadedChangeHandler)
{
// We cannot assert this condition here for the following reason.
// If the [Un]LoadedHandler is added to the current node after the parent
// for this node has been [Un]Loaded but before the current node has been [Un]Loaded
// (example: within the [Un]Loaded handler for the parent), then the IsLoaded
// cache on the current node has been updated to match that of the parent,
// and this Assert will be violated. See BroadcastEventHelper.UpdateHasHandlerFlag
// for further description.
// Debug.Assert(IsLoaded == [false/true],
// "Element should have been [Un]loaded before it is [Un]Loaded back again");
fe.IsLoadedCache = (routedEvent == FrameworkElement.LoadedEvent);
eventRoute.Add(fe);
// Continue walk down subtree
return true;
}
}
}
else
{
// If this is a FrameworkContentElement
FrameworkContentElement fce = (FrameworkContentElement)d;
if (fce != root && routedEvent == FrameworkElement.LoadedEvent && fce.UnloadedPending != null)
{
// If there is a pending Unloaded event wait till we've broadcast
// that event before we can fire the new Loaded event.
fce.FireLoadedOnDescendentsInternal();
}
else if (fce != root && routedEvent == FrameworkElement.UnloadedEvent && fce.LoadedPending != null)
{
// If there is a pending Loaded event abort it because we are now
// being Unloaded.
RemoveLoadedCallback(fce, fce.LoadedPending);
}
else
{
if (fce != root)
{
if (routedEvent == FrameworkElement.LoadedEvent && fce.LoadedPending != null)
{
// If there is a pending Loaded event abort it because we are now
// being Loaded.
RemoveLoadedCallback(fce, fce.LoadedPending);
}
else if (routedEvent == FrameworkElement.UnloadedEvent && fce.UnloadedPending != null)
{
// If there is a pending Unloaded event abort it because we are now
// being Unloaded.
RemoveUnloadedCallback(fce, fce.UnloadedPending);
}
}
// If element has handlers fire the event and continue to walk down the tree
if (fce.SubtreeHasLoadedChangeHandler)
{
// We cannot assert this condition here for the following reason.
// If the [Un]LoadedHandler is added to the current node after the parent
// for this node has been [Un]Loaded but before the current node has been [Un]Loaded
// (example: within the [Un]Loaded handler for the parent), then the IsLoaded
// cache on the current node has been updated to match that of the parent,
// and this Assert will be violated. See BroadcastEventHelper.UpdateHasHandlerFlag
// for further description.
// Debug.Assert(IsLoaded == [false/true],
// "Element should have been [Un]loaded before it is [Un]Loaded back again");
fce.IsLoadedCache = (routedEvent == FrameworkElement.LoadedEvent);
eventRoute.Add(fce);
// Continue walk down subtree
return true;
}
}
}
// Stop walk down subtree
return false;
}
// Callback on visiting each node in the descendency during a broadcast event
private static bool OnBroadcastCallback(DependencyObject d, BroadcastEventData data, bool visitedViaVisualTree)
{
DependencyObject root = data.Root;
RoutedEvent routedEvent = data.RoutedEvent;
List <DependencyObject> eventRoute = data.EventRoute;
if (FrameworkElement.DType.IsInstanceOfType(d))
{
// If this is a FrameworkElement
FrameworkElement fe = (FrameworkElement)d;
if (fe != root && routedEvent == FrameworkElement.LoadedEvent && fe.UnloadedPending != null)
{
// If there is a pending Unloaded event wait till we've broadcast
// that event before we can fire the new Loaded event.
fe.FireLoadedOnDescendentsInternal();
}
else if (fe != root && routedEvent == FrameworkElement.UnloadedEvent && fe.LoadedPending != null)
{
// If there is a pending Loaded event abort it because we are now
// being Unloaded.
RemoveLoadedCallback(fe, fe.LoadedPending);
}
else
{
if (fe != root)
{
if (routedEvent == FrameworkElement.LoadedEvent && fe.LoadedPending != null)
{
// If there is a pending Loaded event abort it because we are now
// being Loaded.
RemoveLoadedCallback(fe, fe.LoadedPending);
}
else if (routedEvent == FrameworkElement.UnloadedEvent && fe.UnloadedPending != null)
{
// If there is a pending Unloaded event abort it because we are now
// being Unloaded.
RemoveUnloadedCallback(fe, fe.UnloadedPending);
}
}
// If element has handlers fire the event and continue to walk down the tree
if (fe.SubtreeHasLoadedChangeHandler)
{
// We cannot assert this condition here for the following reason.
// If the [Un]LoadedHandler is added to the current node after the parent
// for this node has been [Un]Loaded but before the current node has been [Un]Loaded
// (example: within the [Un]Loaded handler for the parent), then the IsLoaded
// cache on the current node has been updated to match that of the parent,
// and this Assert will be violated. See BroadcastEventHelper.UpdateHasHandlerFlag
// for further description.
// Debug.Assert(IsLoaded == [false/true],
// "Element should have been [Un]loaded before it is [Un]Loaded back again");
fe.IsLoadedCache = (routedEvent == FrameworkElement.LoadedEvent);
eventRoute.Add(fe);
// Continue walk down subtree
return(true);
}
}
}
else
{
// If this is a FrameworkContentElement
FrameworkContentElement fce = (FrameworkContentElement)d;
if (fce != root && routedEvent == FrameworkElement.LoadedEvent && fce.UnloadedPending != null)
{
// If there is a pending Unloaded event wait till we've broadcast
// that event before we can fire the new Loaded event.
fce.FireLoadedOnDescendentsInternal();
}
else if (fce != root && routedEvent == FrameworkElement.UnloadedEvent && fce.LoadedPending != null)
{
// If there is a pending Loaded event abort it because we are now
// being Unloaded.
RemoveLoadedCallback(fce, fce.LoadedPending);
}
else
{
if (fce != root)
{
if (routedEvent == FrameworkElement.LoadedEvent && fce.LoadedPending != null)
{
// If there is a pending Loaded event abort it because we are now
// being Loaded.
RemoveLoadedCallback(fce, fce.LoadedPending);
}
else if (routedEvent == FrameworkElement.UnloadedEvent && fce.UnloadedPending != null)
{
// If there is a pending Unloaded event abort it because we are now
// being Unloaded.
RemoveUnloadedCallback(fce, fce.UnloadedPending);
}
}
// If element has handlers fire the event and continue to walk down the tree
if (fce.SubtreeHasLoadedChangeHandler)
{
// We cannot assert this condition here for the following reason.
// If the [Un]LoadedHandler is added to the current node after the parent
// for this node has been [Un]Loaded but before the current node has been [Un]Loaded
// (example: within the [Un]Loaded handler for the parent), then the IsLoaded
// cache on the current node has been updated to match that of the parent,
// and this Assert will be violated. See BroadcastEventHelper.UpdateHasHandlerFlag
// for further description.
// Debug.Assert(IsLoaded == [false/true],
// "Element should have been [Un]loaded before it is [Un]Loaded back again");
fce.IsLoadedCache = (routedEvent == FrameworkElement.LoadedEvent);
eventRoute.Add(fce);
// Continue walk down subtree
return(true);
}
}
}
// Stop walk down subtree
return(false);
}
