protected internal override void OnQueryItems( VirtualPage page, AsyncQueryInfo queryInfo )
{
base.OnQueryItems( page, queryInfo );
DataGridVirtualizingQueryableCollectionViewGroup collectionViewGroup =
this.GetLinkedCollectionViewGroup( page.ParentVirtualList ) as DataGridVirtualizingQueryableCollectionViewGroup;
IQueryable queryableToUse;
int virtualItemCount = collectionViewGroup.VirtualItemCount;
bool queryableIsReversed;
if( ( !m_supportsPrimaryKeyOptimizations ) || ( queryInfo.StartIndex < ( virtualItemCount / 2 ) ) )
{
queryableIsReversed = false;
queryableToUse = collectionViewGroup.Queryable.Slice( queryInfo.StartIndex, queryInfo.RequestedItemCount );
}
else
{
queryableIsReversed = true;
int reversedStartIndex = virtualItemCount - ( queryInfo.StartIndex + queryInfo.RequestedItemCount );
queryableToUse = collectionViewGroup.ReversedQueryable.Slice( reversedStartIndex, queryInfo.RequestedItemCount );
}
System.Threading.ThreadPool.QueueUserWorkItem( new System.Threading.WaitCallback( this.AsyncGatherItems ), new object[] { queryInfo, queryableToUse, queryableIsReversed } );
}
//PageTable object constructor
public PageTable(RealMachine realMachine)
{
_realMachine = realMachine;
for (int i = 0; i < Settings.Default.VirtualPagesCount; i++)
{
VirtualPages[i] = new VirtualPage(i);
}
}
protected internal override void OnQueryItemsCompleted( VirtualPage page, AsyncQueryInfo queryInfo, object[] fetchedItems )
{
DataGridVirtualizingQueryableCollectionView collectionView = this.CollectionView as DataGridVirtualizingQueryableCollectionView;
// The VirtualPageManager was Disposed
if( collectionView == null )
return;
using( collectionView.DeferRefresh() )
{
base.OnQueryItemsCompleted( page, queryInfo, fetchedItems );
}
}
protected internal override void OnAbortQueryItems( VirtualPage page, AsyncQueryInfo queryInfo )
{
DataGridVirtualizingCollectionView collectionView = this.CollectionView as DataGridVirtualizingCollectionView;
// The VirtualPageManager was Disposed
if( collectionView == null )
return;
DataGridVirtualizingCollectionViewGroup collectionViewGroup = this.GetLinkedCollectionViewGroup( page.ParentVirtualList ) as DataGridVirtualizingCollectionViewGroup;
collectionView.OnAbortQueryItems( queryInfo, collectionViewGroup );
base.OnAbortQueryItems( page, queryInfo );
}
public void AddPage( VirtualPage page )
{
Debug.Assert( !m_virtualPages.Contains( page ) );
m_virtualPages.Add( page );
int itemCount = page.Count;
for( int i = 0; i < itemCount; i++ )
{
VirtualizedItemInfo virtualizedItemInfo = page[ i ];
Debug.Assert( !m_objectVersusIndexDictionary.ContainsKey( virtualizedItemInfo.DataItem ) );
Debug.Assert( !m_indexVersusPageDictionary.ContainsKey( virtualizedItemInfo.Index ) );
m_objectVersusIndexDictionary.Add( virtualizedItemInfo.DataItem, virtualizedItemInfo.Index );
m_indexVersusPageDictionary.Add( virtualizedItemInfo.Index, page );
}
}
public void RemovePage( VirtualPage page )
{
Debug.Assert( m_virtualPages.Contains( page ) );
int itemCount = page.Count;
for( int i = 0; i < itemCount; i++ )
{
VirtualizedItemInfo virtualizedItemInfo = page[ i ];
Debug.Assert( m_objectVersusIndexDictionary.ContainsKey( virtualizedItemInfo.DataItem ) );
Debug.Assert( m_indexVersusPageDictionary.ContainsKey( virtualizedItemInfo.Index ) );
Debug.Assert( m_indexVersusPageDictionary[ virtualizedItemInfo.Index ] == page );
m_objectVersusIndexDictionary.Remove( virtualizedItemInfo.DataItem );
m_indexVersusPageDictionary.Remove( virtualizedItemInfo.Index );
}
m_virtualPages.Remove( page );
}
protected internal virtual void OnCommitItems( VirtualPage page, AsyncCommitInfo commitInfo )
{
}
protected internal virtual void OnQueryItemsCompleted( VirtualPage page, AsyncQueryInfo queryInfo, object[] fetchedItems )
{
this.IncrementVersion();
page.ParentVirtualList.FillEmptyPage( queryInfo, fetchedItems );
}
protected internal virtual void OnAbortQueryItems( VirtualPage page, AsyncQueryInfo queryInfo )
{
}
public bool TryGetPageForSourceIndex( int sourceIndex, out VirtualPage page )
{
return m_indexVersusPageDictionary.TryGetValue( sourceIndex, out page );
}
internal virtual void OnVirtualListPageRestarting( VirtualList virtualList, VirtualPage page )
{
Debug.Assert( m_managedLists.Contains( virtualList ) );
LinkedListNode<VirtualPage> pageNode = m_pageNodes.Find( page );
Debug.Assert( pageNode != null );
// RemovePageNode takes care of either raising the AbortQueryData event or aborting the QueryData Dispatcher Operation altogether.
// It also takes care of raising the CommitVirtualData event for loaded pages which contains modified data.
this.QueueCommitDataOrAbortIfRequired( pageNode, false );
}
internal void MovePageToFront( VirtualPage page )
{
// The further from the front a page is, the longer it has been since it was requested.
Debug.Assert( page != null );
LinkedListNode<VirtualPage> firstNode = m_pageNodes.First;
if( firstNode.Value != page )
{
LinkedListNode<VirtualPage> node = m_pageNodes.Find( page );
m_pageNodes.Remove( node );
m_pageNodes.AddFirst( node );
Debug.WriteLineIf( VirtualPageManager.DebugDataVirtualization, "Moved To Front: Page " + page.ToString() );
}
}
protected internal virtual void OnCommitErrorChanged( VirtualPage page, AsyncCommitInfo commitInfo )
{
}
public bool TryGetPageForItem( object item, out VirtualPage page )
{
page = null;
int index;
if( m_objectVersusIndexDictionary.TryGetValue( item, out index ) )
return m_indexVersusPageDictionary.TryGetValue( index, out page );
return false;
}
protected internal virtual void OnCommitItemsCompleted( VirtualPage page, AsyncCommitInfo commitInfo )
{
page.ParentVirtualList.NotifyCommitComplete( commitInfo );
}
protected internal virtual void OnQueryErrorChanged( VirtualPage page, AsyncQueryInfo queryInfo )
{
}
internal void QueueQueryData( VirtualPage page )
{
Debug.Assert( m_managedLists.Contains( page.ParentVirtualList ) );
page.QueueQueryData( this.Dispatcher );
}
internal void RemovePage( VirtualPage page )
{
if( page.IsDisposed )
return;
Debug.Assert( page != null );
//Debug.Assert( !page.IsRestarting );
Debug.Assert( !page.IsDirty );
// A filled page is being removed. Change the version.
this.IncrementVersion();
// Update the table of content of the page's ParentVirtualList
page.ParentVirtualList.TableOfContent.RemovePage( page );
m_pageNodes.Remove( page );
Debug.WriteLineIf( VirtualPageManager.DebugDataVirtualization, "Removed Page: " + page.ToString() );
// Dispose the page since it will never be reused
page.Dispose();
}
internal void QueueCommitData( VirtualPage page )
{
Debug.WriteLineIf( VirtualPageManager.DebugDataVirtualization, "QueueCommitData for page " + page.ToString() );
Debug.Assert( m_managedLists.Contains( page.ParentVirtualList ) );
Debug.Assert( page.IsFilled );
Debug.Assert( page.IsDirty );
if( this.RestartingManager )
this.ShouldRefreshAfterRestart = true;
page.QueueCommitData( this.Dispatcher );
}
internal void AddPage( VirtualPage page, PageInsertPosition insertPosition )
{
if( page == null )
throw new ArgumentNullException( "page", "TODOOC: An internal error occured while paging data. Page cannot be null." );
// We call clean-up before the call to AddFirst since if we do
// it afterward and the page is pending fill, we will remove it.
this.CleanUpAndDisposeUnused();
if( insertPosition == PageInsertPosition.Front )
{
m_pageNodes.AddFirst( page );
}
else
{
m_pageNodes.AddLast( page );
}
Debug.WriteLineIf( VirtualPageManager.DebugDataVirtualization, "Added To " + ( ( insertPosition == PageInsertPosition.Front ) ? "Front" : "Back" ) + ": Page " + page.ToString() );
}
protected internal abstract void OnBuiltInAbort( VirtualPage virtualPage, AsyncQueryInfo queryInfo );
internal virtual void OnVirtualListPageRestarted( VirtualList virtualList, VirtualPage page )
{
Debug.Assert( m_managedLists.Contains( virtualList ) );
Debug.Assert( m_pageNodes.Contains( page ) );
this.RemovePage( page );
}
protected internal abstract void OnQueryItems( VirtualPage page, AsyncQueryInfo queryInfo );
