public FixedCellPanel()
{
// None of the Visual children of the FixedCellPanel will scroll. The needed scrolling
// as demanded by the parent ScrollViewer will be manually transferred to the
// content (m_scrollingPanel) of the ScrollingCellsDecorator below.
m_fixedPanel = new FixedCellSubPanel( this );
m_splitter = new FixedColumnSplitter();
m_scrollingPanel = new VirtualizingFixedCellSubPanel( this );
m_scrollingCellsDecorator = new ScrollingCellsDecorator();
m_scrollingCellsDecorator.Child = m_scrollingPanel;
this.AddVisualChild( m_fixedPanel );
this.AddVisualChild( m_splitter );
this.AddVisualChild( m_scrollingCellsDecorator );
// Used to get the correct item depending of the ZIndex
m_visualChildren.Add( m_fixedPanel );
m_visualChildren.Add( m_splitter );
m_visualChildren.Add( m_scrollingCellsDecorator );
}
void IPrintInfo.UpdateElementVisibility(double horizontalOffset, double viewportWidth, object state)
{
IDictionary <string, object> visibilityState = (IDictionary <string, object>)state;
Debug.Assert(visibilityState != null);
double accumulatedWidth = 0.0d;
bool firstCellInViewportFound = false;
double viewportLimitsHorizontalOffset = horizontalOffset + viewportWidth;
foreach (Cell cell in this.GetVisibleCells())
{
Visibility cellVisibility = cell.Visibility;
if (cellVisibility == Visibility.Collapsed)
{
continue;
}
accumulatedWidth += cell.ActualWidth;
bool isPastViewportStart = accumulatedWidth > horizontalOffset;
bool isBeforeViewportEnd = isPastViewportStart && (accumulatedWidth <= (viewportLimitsHorizontalOffset));
bool isFirstInViewport = (isPastViewportStart) && (!firstCellInViewportFound);
if (isFirstInViewport)
{
firstCellInViewportFound = true;
}
if (isPastViewportStart)
{
// The cell is past the Viewport's start.
if ((isBeforeViewportEnd) || (isFirstInViewport))
{
// Either the cell is completely visible in the Viewport
// or we face a cell which is the first in the Viewport but does not completely fit in the Viewport.
FixedCellSubPanel.RestoreCellVisibility(cell, visibilityState);
}
else if (cellVisibility == Visibility.Visible)
{
// The cell is past the Viewport's end.
FixedCellSubPanel.HideCell(cell, visibilityState);
}
}
else if (cellVisibility == Visibility.Visible)
{
// The cell is before the Viewport's start.
FixedCellSubPanel.HideCell(cell, visibilityState);
}
}
}