/// <summary>
/// Adjusts the column width relative to the given <see cref="MultiHeaderCell"/> based on its width.
/// </summary>
/// <param name="headerCell">A <see cref="MultiHeaderCell"/> object.</param>
private void AdjustColumnsWidth(MultiHeaderCell headerCell)
{
if (headerCell == null || !AutoSizeColumnsBasedOnAdditionalHeadersContent || AutoSizeColumnsMode == DataGridViewAutoSizeColumnsMode.None)
{
return;
}
// Calculate the total width of the base columns the headerCell spans
var spanningInfo = MultiHeaderCellsSpanningInfo.GetHeaderCellSpanningInfo(this, headerCell);
// Nothing to do if the spanning columns width already accomodates space for the computed headerCell's width
if (spanningInfo.TotalSpanningWidth >= headerCell.CellSize.Width)
{
return;
}
// Re-adjust grid's columns widths spanned by the headerCell
int remainder;
int proportionalWidthToIncrease = Math.DivRem(headerCell.CellSize.Width - spanningInfo.VisibleWidth, headerCell.ColumnSpan, out remainder);
if (remainder > 0)
{
proportionalWidthToIncrease++;
}
int lastColumnIndex = headerCell.GetLastBaseColumnIndexFromSpan(Columns.Count);
for (int idx = headerCell.ColumnIndex; idx <= lastColumnIndex; idx++)
{
DataGridViewColumn spanningColumn = Columns[idx];
int newWidth = spanningColumn.Width + proportionalWidthToIncrease;
_skipColumnWidthsAdjustment = true;
spanningColumn.AutoSizeMode = DataGridViewAutoSizeColumnMode.None;
spanningColumn.Width = newWidth;
_skipColumnWidthsAdjustment = false;
}
}
/// <summary>
/// Raises the <see cref="Control.Paint"/> event.
/// </summary>
/// <param name="e">A <see cref="PaintEventArgs"/> that contains the event data.</param>
protected override void OnPaint(PaintEventArgs e)
{
base.OnPaint(e);
// Enforce that the alignment of the original header text is at the bottom, so the other header rows can be drawn correctly.
ColumnHeadersDefaultCellStyle.Alignment = BaseColumnHeadersTextAlignment.ToBottomAlignment();
// Get the total height for header rows
ColumnHeadersHeight = GetTotalHeaderRowsHeight();
if (_multiHeaderRowsList == null || _multiHeaderRowsList.Count == 0)
{
return;
}
// Set other properties and process each additional row.
var rowsQuantity = _multiHeaderRowsList.Count;
var foregroundBrush = new SolidBrush(ColumnHeadersDefaultCellStyle.ForeColor);
var backgroundBrush = new SolidBrush(ColumnHeadersDefaultCellStyle.BackColor);
int accumulatedRowHeights = 0;
for (int rowIndex = 0; rowIndex < rowsQuantity; rowIndex++)
{
int reversedRowIndex = ReverseMultiHeaderRowOrder ? rowsQuantity - rowIndex - 1 : rowIndex;
var headerRow = _multiHeaderRowsList[reversedRowIndex];
var headerRowHeight = UseFixedColumnHeadersHeight ? FixedColumnHeadersHeight : headerRow.Height;
foreach (var headerCell in headerRow.Where(headerCell => !headerCell.InSpan))
{
// Calculate the information for the cells being spanned by the currently processed headerCell.
var spanningInfo = MultiHeaderCellsSpanningInfo.GetHeaderCellSpanningInfo(this, headerCell);
// If the spanning columns are not fully visible, then skip.
if (spanningInfo.VisibleArea == Rectangle.Empty)
{
continue;
}
// Compute the rectangle areas to manually draw the additional header
var headerAreaWithSeparatorsRectangle = new Rectangle(
spanningInfo.VisibleArea.Left,
spanningInfo.VisibleArea.Top + accumulatedRowHeights,
spanningInfo.VisibleWidth,
headerRowHeight);
e.Graphics.SetClip(headerAreaWithSeparatorsRectangle);
var headerDrawableAreaRectangle = new Rectangle(
headerAreaWithSeparatorsRectangle.Left - spanningInfo.LeftOverflowingWidth,
headerAreaWithSeparatorsRectangle.Top,
spanningInfo.TotalSpanningWidth - Math.Max(ColumnHeadersSeparatorWidth, spanningInfo.RightDividerWidth + 1),
headerAreaWithSeparatorsRectangle.Height - ColumnHeadersSeparatorWidth);
var topPadding = UseColumnPaddings ? headerCell.Style.Padding.Top : 0;
var bottomPadding = UseColumnPaddings ? headerCell.Style.Padding.Bottom : 0;
var leftPadding = UseColumnPaddings ? headerCell.Style.Padding.Left : 0;
var rightPadding = UseColumnPaddings ? headerCell.Style.Padding.Right : 0;
var textAreaRectangle = new Rectangle(
headerDrawableAreaRectangle.Left + leftPadding,
headerDrawableAreaRectangle.Top + topPadding,
headerDrawableAreaRectangle.Width - leftPadding - rightPadding,
headerDrawableAreaRectangle.Height - bottomPadding - topPadding);
// Draw area with separators
backgroundBrush.Color = ColumnHeadersSeparatorColor;
e.Graphics.FillRectangle(backgroundBrush, headerAreaWithSeparatorsRectangle);
// Draw header area with its background color on top of the area with separators to emulate the separators
backgroundBrush.Color = headerCell.Style.BackColor;
e.Graphics.FillRectangle(backgroundBrush, headerDrawableAreaRectangle);
// Draw the header text
foregroundBrush.Color = headerCell.Style.ForeColor.IsEmpty
? ColumnHeadersDefaultCellStyle.ForeColor
: headerCell.Style.ForeColor;
var headerFont = headerCell.Style.Font ?? ColumnHeadersDefaultCellStyle.Font;
e.Graphics.DrawString(headerCell.Text, headerFont, foregroundBrush, textAreaRectangle, headerCell.Style.Alignment.ToStringFormat());
}
accumulatedRowHeights += headerRowHeight;
}
foregroundBrush.Dispose();
backgroundBrush.Dispose();
}
