/// <summary> /// Measures the children of a <see cref="T:Avalonia.Controls.Primitives.DataGridColumnHeadersPresenter" /> 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.DataGridColumnHeadersPresenter" /> determines it needs during layout, based on its calculations of child object allocated sizes. /// </returns> protected override Size MeasureOverride(Size availableSize) { if (OwningGrid == null) { return(base.MeasureOverride(availableSize)); } if (!OwningGrid.AreColumnHeadersVisible) { return(Size.Empty); } double height = OwningGrid.ColumnHeaderHeight; bool autoSizeHeight; if (double.IsNaN(height)) { // No explicit height values were set so we can autosize height = 0; autoSizeHeight = true; } else { autoSizeHeight = false; } double totalDisplayWidth = 0; OwningGrid.ColumnsInternal.EnsureVisibleEdgedColumnsWidth(); DataGridColumn lastVisibleColumn = OwningGrid.ColumnsInternal.LastVisibleColumn; foreach (DataGridColumn column in OwningGrid.ColumnsInternal.GetVisibleColumns()) { // Measure each column header bool autoGrowWidth = column.Width.IsAuto || column.Width.IsSizeToHeader; DataGridColumnHeader columnHeader = column.HeaderCell; if (column != lastVisibleColumn) { columnHeader.UpdateSeparatorVisibility(lastVisibleColumn); } // If we're not using star sizing or the current column can't be resized, // then just set the display width according to the column's desired width if (!OwningGrid.UsesStarSizing || (!column.ActualCanUserResize && !column.Width.IsStar)) { // In the edge-case where we're given infinite width and we have star columns, the // star columns grow to their predefined limit of 10,000 (or their MaxWidth) double newDisplayWidth = column.Width.IsStar ? Math.Min(column.ActualMaxWidth, DataGrid.DATAGRID_maximumStarColumnWidth) : Math.Max(column.ActualMinWidth, Math.Min(column.ActualMaxWidth, column.Width.DesiredValue)); column.SetWidthDisplayValue(newDisplayWidth); } // If we're auto-growing the column based on the header content, we want to measure it at its maximum value if (autoGrowWidth) { columnHeader.Measure(new Size(column.ActualMaxWidth, double.PositiveInfinity)); OwningGrid.AutoSizeColumn(column, columnHeader.DesiredSize.Width); column.ComputeLayoutRoundedWidth(totalDisplayWidth); } else if (!OwningGrid.UsesStarSizing) { column.ComputeLayoutRoundedWidth(totalDisplayWidth); columnHeader.Measure(new Size(column.LayoutRoundedWidth, double.PositiveInfinity)); } // We need to track the largest height in order to auto-size if (autoSizeHeight) { height = Math.Max(height, columnHeader.DesiredSize.Height); } totalDisplayWidth += column.ActualWidth; } // If we're using star sizing (and we're not waiting for an auto-column to finish growing) // then we will resize all the columns to fit the available space. if (OwningGrid.UsesStarSizing && !OwningGrid.AutoSizingColumns) { double adjustment = Double.IsPositiveInfinity(availableSize.Width) ? OwningGrid.CellsWidth : availableSize.Width - totalDisplayWidth; totalDisplayWidth += adjustment - OwningGrid.AdjustColumnWidths(0, adjustment, false); // Since we didn't know the final widths of the columns until we resized, // we waited until now to measure each header double leftEdge = 0; foreach (DataGridColumn column in OwningGrid.ColumnsInternal.GetVisibleColumns()) { column.ComputeLayoutRoundedWidth(leftEdge); column.HeaderCell.Measure(new Size(column.LayoutRoundedWidth, double.PositiveInfinity)); if (autoSizeHeight) { height = Math.Max(height, column.HeaderCell.DesiredSize.Height); } leftEdge += column.ActualWidth; } } // Add the filler column if it's not represented. We won't know whether we need it or not until Arrange DataGridFillerColumn fillerColumn = OwningGrid.ColumnsInternal.FillerColumn; if (!fillerColumn.IsRepresented) { Debug.Assert(!Children.Contains(fillerColumn.HeaderCell)); fillerColumn.HeaderCell.AreSeparatorsVisible = false; Children.Insert(OwningGrid.ColumnsInternal.Count, fillerColumn.HeaderCell); fillerColumn.IsRepresented = true; // Optimize for the case where we don't need the filler cell fillerColumn.HeaderCell.IsVisible = false; } fillerColumn.HeaderCell.Measure(new Size(double.PositiveInfinity, double.PositiveInfinity)); if (DragIndicator != null) { DragIndicator.Measure(new Size(double.PositiveInfinity, double.PositiveInfinity)); } if (DropLocationIndicator != null) { DropLocationIndicator.Measure(new Size(double.PositiveInfinity, double.PositiveInfinity)); } OwningGrid.ColumnsInternal.EnsureVisibleEdgedColumnsWidth(); return(new Size(OwningGrid.ColumnsInternal.VisibleEdgedColumnsWidth, height)); }
/// <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); }