/// <summary>
/// ReleaseOnChannel
/// </summary>
void DUCE.IResource.ReleaseOnChannel(DUCE.Channel channel)
{
// reconsider the need for this lock
using (CompositionEngineLock.Acquire())
{
Debug.Assert(_duceResource.IsOnChannel(channel));
//release from this channel
_duceResource.ReleaseOnChannel(channel);
if (!_duceResource.IsOnAnyChannel)
{
// If this was the last reference on the channel then clear up our state.
// Again, we assume here that if the target DependencyObject is animated that
// it will be associated with a Dispatcher and that this animation resource
// will also be associated with that Dispatcher's channel.
DependencyObject d = (DependencyObject)_dependencyObject.Target;
// DependencyObject shouldn't have been garbage collected before we've
// released all of its property animation resources.
Debug.Assert(d != null);
// The target DependencyObject should be associated with a Dispatcher.
Debug.Assert(d.Dispatcher != null);
// Make sure the target belongs to this thread
Debug.Assert(d.CheckAccess());
// If we're invalid, that means we've added our _updateResourceHandler to the
// MediaContext's ResourcesUpdated event. Since we've been entirely released
// from the channel we can cancel this update by removing the handler.
if (!_isValid)
{
MediaContext mediaContext = MediaContext.From(d.Dispatcher);
mediaContext.ResourcesUpdated -= _updateResourceHandler;
_isValid = true;
}
_updateResourceHandler = null;
}
}
}
/// <summary>
/// Internal method to set the root visual.
/// </summary>
/// <param name="visual">Root visual, can be null, but can not be a child of another
/// Visual.</param>
private void SetRootVisual(Visual visual)
{
// We need to make this function robust by leaving the
// _rootVisual in a consistent state.
if (visual != null &&
(visual._parent != null ||
visual.IsRootElement))
{
// If a Visual has already a parent it can not be the root in a CompositionTarget because
// otherwise we would have two CompositionTargets party on the same Visual tree.
// If want to allow this we need to explicitly add support for this.
throw new System.ArgumentException(SR.Get(SRID.CompositionTarget_RootVisual_HasParent));
}
DUCE.ChannelSet channelSet = MediaContext.From(Dispatcher).GetChannels();
DUCE.Channel channel = channelSet.Channel;
if (_rootVisual.Value != null && _contentRoot.IsOnChannel(channel))
{
ClearRootNode(channel);
((DUCE.IResource)_rootVisual.Value).ReleaseOnChannel(channel);
_rootVisual.Value.IsRootElement = false;
}
_rootVisual.Value = visual;
if (_rootVisual.Value != null)
{
_rootVisual.Value.IsRootElement = true;
_rootVisual.Value.SetFlagsOnAllChannels(
true,
VisualProxyFlags.IsSubtreeDirtyForRender);
}
}