/// <summary>
/// Measures the children of a <see cref="T:System.Windows.Controls.Primitives.DataGridCellsPresenter"/> 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:System.Windows.Controls.Primitives.DataGridCellsPresenter"/> determines it needs during layout, based on its calculations of child object allocated sizes.
/// </returns>
protected override Size MeasureOverride(Size availableSize)
{
if (this.OwningGrid == null)
{
return(base.MeasureOverride(availableSize));
}
bool autoSizeHeight;
double measureHeight;
if (double.IsNaN(this.OwningGrid.RowHeight))
{
// No explicit height values were set so we can autosize
autoSizeHeight = true;
measureHeight = double.PositiveInfinity;
}
else
{
this.DesiredHeight = this.OwningGrid.RowHeight;
measureHeight = this.DesiredHeight;
autoSizeHeight = false;
}
double frozenLeftEdge = 0;
double totalDisplayWidth = 0;
double scrollingLeftEdge = -this.OwningGrid.HorizontalOffset;
this.OwningGrid.ColumnsInternal.EnsureVisibleEdgedColumnsWidth();
DataGridColumn lastVisibleColumn = this.OwningGrid.ColumnsInternal.LastVisibleColumn;
foreach (DataGridColumn column in this.OwningGrid.ColumnsInternal.GetVisibleColumns())
{
DataGridCell cell = this.OwningRow.Cells[column.Index];
// Measure the entire first row to make the horizontal scrollbar more accurate
bool shouldDisplayCell = ShouldDisplayCell(column, frozenLeftEdge, scrollingLeftEdge) || this.OwningRow.Index == 0;
EnsureCellDisplay(cell, shouldDisplayCell);
if (shouldDisplayCell)
{
DataGridLength columnWidth = column.Width;
bool autoGrowWidth = columnWidth.IsSizeToCells || columnWidth.IsAuto;
if (column != lastVisibleColumn)
{
cell.EnsureGridLine(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 (!this.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 cell content, we want to measure it at its maximum value
if (autoGrowWidth)
{
cell.Measure(new Size(column.ActualMaxWidth, measureHeight));
this.OwningGrid.AutoSizeColumn(column, cell.DesiredSize.Width);
column.ComputeLayoutRoundedWidth(totalDisplayWidth);
}
else if (!this.OwningGrid.UsesStarSizing)
{
column.ComputeLayoutRoundedWidth(scrollingLeftEdge);
cell.Measure(new Size(column.LayoutRoundedWidth, measureHeight));
}
// We need to track the largest height in order to auto-size
if (autoSizeHeight)
{
this.DesiredHeight = Math.Max(this.DesiredHeight, cell.DesiredSize.Height);
}
}
if (column.IsFrozen)
{
frozenLeftEdge += column.ActualWidth;
}
scrollingLeftEdge += column.ActualWidth;
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 (this.OwningGrid.UsesStarSizing && !this.OwningGrid.AutoSizingColumns)
{
double adjustment = this.OwningGrid.CellsWidth - totalDisplayWidth;
this.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 cell
double leftEdge = 0;
foreach (DataGridColumn column in this.OwningGrid.ColumnsInternal.GetVisibleColumns())
{
DataGridCell cell = this.OwningRow.Cells[column.Index];
column.ComputeLayoutRoundedWidth(leftEdge);
cell.Measure(new Size(column.LayoutRoundedWidth, measureHeight));
if (autoSizeHeight)
{
this.DesiredHeight = Math.Max(this.DesiredHeight, cell.DesiredSize.Height);
}
leftEdge += column.ActualWidth;
}
}
// Measure FillerCell, we're doing it unconditionally here because we don't know if we'll need the filler
// column and we don't want to cause another Measure if we do
this.OwningRow.FillerCell.Measure(new Size(double.PositiveInfinity, this.DesiredHeight));
this.OwningGrid.ColumnsInternal.EnsureVisibleEdgedColumnsWidth();
return(new Size(this.OwningGrid.ColumnsInternal.VisibleEdgedColumnsWidth, this.DesiredHeight));
}
/// <summary>
/// Measures the children of a <see cref="T:System.Windows.Controls.Primitives.DataGridCellsPresenter" /> 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:System.Windows.Controls.Primitives.DataGridCellsPresenter" /> determines it needs during layout, based on its calculations of child object allocated sizes.
/// </returns>
protected override Size MeasureOverride(Size availableSize)
{
if (this.OwningGrid == null)
{
return(base.MeasureOverride(availableSize));
}
bool autoSizeHeight;
double measureHeight;
if (double.IsNaN(this.OwningGrid.RowHeight))
{
// No explicit height values were set so we can autosize
autoSizeHeight = true;
measureHeight = double.PositiveInfinity;
}
else
{
this.DesiredHeight = this.OwningGrid.RowHeight;
measureHeight = this.DesiredHeight;
autoSizeHeight = false;
}
DataGridColumn lastVisibleColumn = this.OwningGrid.ColumnsInternal.LastVisibleColumn;
double totalCellsWidth = this.OwningGrid.ColumnsInternal.VisibleEdgedColumnsWidth;
double measureWidth;
double frozenLeftEdge = 0;
double scrollingLeftEdge = -this.OwningGrid.HorizontalOffset;
foreach (DataGridColumn column in this.OwningGrid.ColumnsInternal.GetVisibleColumns())
{
DataGridCell cell = this.OwningRow.Cells[column.Index];
// Measure the entire first row to make the horizontal scrollbar more accurate
bool shouldDisplayCell = ShouldDisplayCell(column, frozenLeftEdge, scrollingLeftEdge) || this.OwningRow.Index == 0;
EnsureCellDisplay(cell, shouldDisplayCell);
if (shouldDisplayCell)
{
DataGridLength columnWidth = column.EffectiveWidth;
measureWidth = columnWidth.IsAbsolute ? column.ActualWidth : column.ActualMaxWidth;
bool autoGrowWidth = columnWidth.IsSizeToCells || columnWidth.IsAuto;
cell.Measure(new Size(measureWidth, measureHeight));
if (column != lastVisibleColumn)
{
cell.EnsureGridLine(lastVisibleColumn);
}
if (autoSizeHeight)
{
this.DesiredHeight = Math.Max(this.DesiredHeight, cell.DesiredSize.Height);
}
if (autoGrowWidth && cell.DesiredSize.Width > column.DesiredWidth)
{
column.DesiredWidth = cell.DesiredSize.Width;
}
}
if (column.IsFrozen)
{
frozenLeftEdge += column.ActualWidth;
}
scrollingLeftEdge += column.ActualWidth;
}
// Measure FillerCell, we're doing it unconditionally here because we don't know if we'll need the filler
// column and we don't want to cause another Measure if we do
this.OwningRow.FillerCell.Measure(new Size(double.PositiveInfinity, this.DesiredHeight));
return(new Size(totalCellsWidth, this.DesiredHeight));
}
