/// <summary>
/// Measures the children of a <see cref="T:Avalonia.Controls.Primitives.DataGridRowsPresenter" /> to
/// prepare for arranging them during the <see cref="M:System.Windows.FrameworkElement.ArrangeOverride(System.Windows.Size)" /> pass.
/// </summary>
/// <param name="availableSize">
/// The available size that this element can give to child elements. Indicates an upper limit that child elements should not exceed.
/// </param>
/// <returns>
/// The size that the <see cref="T:Avalonia.Controls.Primitives.DataGridRowsPresenter" /> determines it needs during layout, based on its calculations of child object allocated sizes.
/// </returns>
protected override Size MeasureOverride(Size availableSize)
{
if (availableSize.Height == 0 || OwningGrid == null)
{
return(base.MeasureOverride(availableSize));
}
// If the Width of our RowsPresenter changed then we need to invalidate our rows
bool invalidateRows = (!OwningGrid.RowsPresenterAvailableSize.HasValue || availableSize.Width != OwningGrid.RowsPresenterAvailableSize.Value.Width) &&
!double.IsInfinity(availableSize.Width);
// The DataGrid uses the RowsPresenter available size in order to autogrow
// and calculate the scrollbars
OwningGrid.RowsPresenterAvailableSize = availableSize;
OwningGrid.RowsPresenterEstimatedAvailableHeight = CalculateEstimatedAvailableHeight(availableSize);
OwningGrid.OnRowsMeasure();
double totalHeight = -OwningGrid.NegVerticalOffset;
double totalCellsWidth = OwningGrid.ColumnsInternal.VisibleEdgedColumnsWidth;
double headerWidth = 0;
foreach (Control element in OwningGrid.DisplayData.GetScrollingElements())
{
DataGridRow row = element as DataGridRow;
if (row != null)
{
if (invalidateRows)
{
row.InvalidateMeasure();
}
}
element.Measure(new Size(double.PositiveInfinity, double.PositiveInfinity));
if (row != null && row.HeaderCell != null)
{
headerWidth = Math.Max(headerWidth, row.HeaderCell.DesiredSize.Width);
}
else if (element is DataGridRowGroupHeader groupHeader && groupHeader.HeaderCell != null)
{
headerWidth = Math.Max(headerWidth, groupHeader.HeaderCell.DesiredSize.Width);
}
totalHeight += element.DesiredSize.Height;
}
OwningGrid.RowHeadersDesiredWidth = headerWidth;
// Could be positive infinity depending on the DataGrid's bounds
OwningGrid.AvailableSlotElementRoom = availableSize.Height - totalHeight;
totalHeight = Math.Max(0, totalHeight);
return(new Size(totalCellsWidth + headerWidth, totalHeight));
}
private void GridSplitter_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
//This is necessary because the DataGrid will not refresh the hidden contents otherwise.
IList <IGanttNode> nodes = (IList <IGanttNode>)TaskGrid.ItemsSource;
foreach (IGanttNode node in nodes)
{
DataGridRow row = TaskGrid.GetDataItemRow(node);
if (row != null)
{
row.InvalidateMeasure();
}
}
}
/// <summary>
/// Measures the children of a <see cref="DataGridRowsPresenter"/> to
/// prepare for arranging them during the <see cref="M:System.Windows.FrameworkElement.ArrangeOverride(System.Windows.Size)"/> pass.
/// </summary>
/// <param name="availableSize">
/// The available size that this element can give to child elements. Indicates an upper limit that child elements should not exceed.
/// </param>
/// <returns>
/// The size that the <see cref="DataGridRowsPresenter"/> determines it needs during layout, based on its calculations of child object allocated sizes.
/// </returns>
protected override Size MeasureOverride(Size availableSize)
{
if (availableSize.Height == 0 || this.OwningGrid == null)
{
return(base.MeasureOverride(availableSize));
}
// If the Width of our RowsPresenter changed then we need to invalidate our rows
bool invalidateRows =
(!this.OwningGrid.RowsPresenterAvailableSize.HasValue || availableSize.Width != this.OwningGrid.RowsPresenterAvailableSize.Value.Width) &&
!double.IsInfinity(availableSize.Width);
// The DataGrid uses the RowsPresenter available size in order to autogrow
// and calculate the scrollbars
this.OwningGrid.RowsPresenterAvailableSize = availableSize;
this.OwningGrid.OnRowsMeasure();
double totalHeight = -this.OwningGrid.NegVerticalOffset;
double totalCellsWidth = this.OwningGrid.ColumnsInternal.VisibleEdgedColumnsWidth;
double headerWidth = 0;
foreach (UIElement element in this.OwningGrid.DisplayData.GetScrollingElements())
{
DataGridRow row = element as DataGridRow;
if (row != null)
{
if (invalidateRows)
{
row.InvalidateMeasure();
}
}
element.Measure(new Size(double.PositiveInfinity, double.PositiveInfinity));
if (row != null && row.HeaderCell != null)
{
headerWidth = Math.Max(headerWidth, row.HeaderCell.DesiredSize.Width);
}
else
{
DataGridRowGroupHeader groupHeader = element as DataGridRowGroupHeader;
if (groupHeader != null && groupHeader.HeaderCell != null)
{
headerWidth = Math.Max(headerWidth, groupHeader.HeaderCell.DesiredSize.Width);
}
}
totalHeight += element.DesiredSize.Height;
}
this.OwningGrid.RowHeadersDesiredWidth = headerWidth;
// Could be positive infinity depending on the DataGrid's bounds
this.OwningGrid.AvailableSlotElementRoom = availableSize.Height - totalHeight;
// TODO: totalHeight can be negative if we've just collapsed details. This is a workaround,
// the real fix is to correct NegVerticalOffset.
totalHeight = Math.Max(0, totalHeight);
return(new Size(totalCellsWidth + headerWidth, totalHeight));
}