/// <summary>
/// Arranges the content of the <see cref="T:Avalonia.Controls.Primitives.DataGridColumnHeadersPresenter" />.
/// </summary>
/// <returns>
/// The actual size used by the <see cref="T:Avalonia.Controls.Primitives.DataGridColumnHeadersPresenter" />.
/// </returns>
/// <param name="finalSize">
/// The final area within the parent that this element should use to arrange itself and its children.
/// </param>
protected override Size ArrangeOverride(Size finalSize)
{
if (OwningGrid == null)
{
return(base.ArrangeOverride(finalSize));
}
if (OwningGrid.AutoSizingColumns)
{
// When we initially load an auto-column, we have to wait for all the rows to be measured
// before we know its final desired size. We need to trigger a new round of measures now
// that the final sizes have been calculated.
OwningGrid.AutoSizingColumns = false;
return(base.ArrangeOverride(finalSize));
}
double dragIndicatorLeftEdge = 0;
double frozenLeftEdge = 0;
double scrollingLeftEdge = -OwningGrid.HorizontalOffset;
foreach (DataGridColumn dataGridColumn in OwningGrid.ColumnsInternal.GetVisibleColumns())
{
DataGridColumnHeader columnHeader = dataGridColumn.HeaderCell;
Debug.Assert(columnHeader.OwningColumn == dataGridColumn);
if (dataGridColumn.IsFrozen)
{
columnHeader.Arrange(new Rect(frozenLeftEdge, 0, dataGridColumn.LayoutRoundedWidth, finalSize.Height));
columnHeader.Clip = null; // The layout system could have clipped this becaues it's not aware of our render transform
if (DragColumn == dataGridColumn && DragIndicator != null)
{
dragIndicatorLeftEdge = frozenLeftEdge + DragIndicatorOffset;
}
frozenLeftEdge += dataGridColumn.ActualWidth;
}
else
{
columnHeader.Arrange(new Rect(scrollingLeftEdge, 0, dataGridColumn.LayoutRoundedWidth, finalSize.Height));
EnsureColumnHeaderClip(columnHeader, dataGridColumn.ActualWidth, finalSize.Height, frozenLeftEdge, scrollingLeftEdge);
if (DragColumn == dataGridColumn && DragIndicator != null)
{
dragIndicatorLeftEdge = scrollingLeftEdge + DragIndicatorOffset;
}
}
scrollingLeftEdge += dataGridColumn.ActualWidth;
}
if (DragColumn != null)
{
if (DragIndicator != null)
{
EnsureColumnReorderingClip(DragIndicator, finalSize.Height, frozenLeftEdge, dragIndicatorLeftEdge);
var height = DragIndicator.Bounds.Height;
if (height <= 0)
{
height = DragIndicator.DesiredSize.Height;
}
DragIndicator.Arrange(new Rect(dragIndicatorLeftEdge, 0, DragIndicator.Bounds.Width, height));
}
if (DropLocationIndicator != null)
{
if (DropLocationIndicator is Control element)
{
EnsureColumnReorderingClip(element, finalSize.Height, frozenLeftEdge, DropLocationIndicatorOffset);
}
DropLocationIndicator.Arrange(new Rect(DropLocationIndicatorOffset, 0, DropLocationIndicator.Bounds.Width, DropLocationIndicator.Bounds.Height));
}
}
// Arrange filler
OwningGrid.OnFillerColumnWidthNeeded(finalSize.Width);
DataGridFillerColumn fillerColumn = OwningGrid.ColumnsInternal.FillerColumn;
if (fillerColumn.FillerWidth > 0)
{
fillerColumn.HeaderCell.IsVisible = true;
fillerColumn.HeaderCell.Arrange(new Rect(scrollingLeftEdge, 0, fillerColumn.FillerWidth, finalSize.Height));
}
else
{
fillerColumn.HeaderCell.IsVisible = false;
}
// This needs to be updated after the filler column is configured
DataGridColumn lastVisibleColumn = OwningGrid.ColumnsInternal.LastVisibleColumn;
if (lastVisibleColumn != null)
{
lastVisibleColumn.HeaderCell.UpdateSeparatorVisibility(lastVisibleColumn);
}
return(finalSize);
}