private void RecycleCandidate( UIElement container )
{
int realizedIndex;
if( !m_oldLayoutedContainers.TryGetValue( container, out realizedIndex ) )
return;
m_oldLayoutedContainers.Remove( container );
var containerInfo = new LayoutedContainerInfo( realizedIndex, container );
// Keep the focused container active by putting it in the layouted containers collection.
if( container == m_focusedContainer )
{
m_newLayoutedContainers.Add( containerInfo );
}
else
{
m_itemsHost.RecycleContainer( m_generator, containerInfo );
}
}
private void RecycleContainer( ICustomItemContainerGenerator generator, LayoutedContainerInfo containerInfo )
{
Debug.Assert( containerInfo != null );
var index = containerInfo.RealizedIndex;
if( ( generator != null ) && ( index >= 0 ) )
{
try
{
var position = generator.GeneratorPositionFromIndex( index );
generator.Remove( position, 1 );
}
catch
{
Debug.Fail( "Unable to remove container for containerIndex " + index );
}
}
this.ClearContainer( containerInfo.Container );
}
protected LayoutedContainerInfo CreateContainer( int realizedIndex )
{
if( ( realizedIndex < 0 ) || ( realizedIndex >= m_itemCount ) )
return null;
this.RecycleCandidates( realizedIndex );
var position = m_generator.GeneratorPositionFromIndex( realizedIndex );
using( m_generator.StartAt( position, GeneratorDirection.Forward, true ) )
{
var container = m_itemsHost.GenerateContainer( m_generator, realizedIndex, m_forceMeasure );
if( container == null )
return null;
m_remainingViewportHeight -= container.DesiredSize.Height;
m_oldLayoutedContainers.Remove( container );
var containerInfo = new LayoutedContainerInfo( realizedIndex, container );
m_newLayoutedContainers.Add( containerInfo );
return containerInfo;
}
}
