/// <summary>
/// Content arrangement.
/// </summary>
/// <param name="arrangeSize">Arrange size</param>
protected override Size ArrangeOverride(Size arrangeSize)
{
if (Owner.FrozenRowCount == 0)
{
return(base.ArrangeOverride(arrangeSize));
}
var rcChild = new Rect(arrangeSize);
int frozenRowCount = 0;
double nextFrozenRowStart = 0.0; //indicates the start position for next frozen row
double nextNonFrozenRowStart = 0.0; //indicates the start position for next non-frozen row
double dataGridVerticalScrollStartY = 0.0; //indicates the start position of the vertical scroll bar.
//
// determine the vertical offset, row panel offset and other coordinates used for arrange of children
//
if (Owner != null)
{
double physicalOffset;
var originPoint = new Point(0, 0);
IScrollInfo scrollInfo = this;
{
double verticalOffset = scrollInfo.VerticalOffset;
physicalOffset = -1.0 * ComputePhysicalFromLogicalOffset(verticalOffset, false);
rcChild.X = -1.0 * scrollInfo.HorizontalOffset;
}
double sbOffset = VerticalScrollBar.TransformToAncestor(ParentPresenter).Transform(originPoint).Y;
double rowsPanelOffset = TransformToAncestor(ParentPresenter).Transform(originPoint).Y; //indicates the offset of rows panel from the start of viewport
nextFrozenRowStart = 0.0;
double viewportStartY = sbOffset - rowsPanelOffset;
//indicates the start of viewport with respect to coordinate system of row panel
nextNonFrozenRowStart -= physicalOffset - viewportStartY;
if (Owner.FrozenRowCount != null)
{
frozenRowCount = (int)Owner.FrozenRowCount;
}
//Debug.WriteLine(string.Format(
// "verticalOffset: {0}, physicalOffset: {1}, sbOffset: {2}, viewportStartY: {3}, nextNonFrozeRowStart: {4}",
// verticalOffset,
// physicalOffset,
// sbOffset,
// viewportStartY,
// nextNonFrozenRowStart));
}
//
// Arrange and Position Children.
//
var children = GetRealizedChildren;
for (int i = 0; i < children.Count; ++i)
{
// we are looping through the actual containers; the visual children of this panel.
var container = (UIElement)children[i];
var childSize = container.DesiredSize;
//TODO: need to handle virtualization
// container = ParentPresenter.ItemContainerGenerator.ContainerFromIndex(i) as UIElement;
// if (container != null)
// {
// childSize = container.DesiredSize;
// }
// else
// {
// //TODO: handle sizing for virtualization
// }
//}
rcChild.Height = childSize.Height;
rcChild.Width = Math.Max(arrangeSize.Width, childSize.Width);
if (i < frozenRowCount)
{
rcChild.Y = nextFrozenRowStart;
nextFrozenRowStart += childSize.Height;
dataGridVerticalScrollStartY += childSize.Height;
}
else
{
if (DoubleUtil.LessThan(nextNonFrozenRowStart, nextFrozenRowStart))
{
IScrollInfo scrollInfo = this;
var verticalOffset = scrollInfo.VerticalOffset;
if (DoubleUtil.LessThan(nextNonFrozenRowStart + childSize.Height, nextFrozenRowStart))
{
nextNonFrozenRowStart += childSize.Height;
}
else
{
double rowChoppedHeight = nextFrozenRowStart - nextNonFrozenRowStart;
if (DoubleUtil.AreClose(rowChoppedHeight, 0.0))
{
nextNonFrozenRowStart = nextFrozenRowStart + childSize.Height;
}
else
{
double clipHeight = childSize.Height - rowChoppedHeight;
nextNonFrozenRowStart = nextFrozenRowStart + clipHeight;
}
}
rcChild.Y = nextFrozenRowStart;
}
else
{
rcChild.Y = nextNonFrozenRowStart;
nextNonFrozenRowStart += childSize.Height;
}
}
container.Arrange(rcChild);
}
if (Owner != null)
{
Owner.NonFrozenRowsViewportVerticalOffset = dataGridVerticalScrollStartY;
}
return(arrangeSize);
}