protected override Size MeasureOverride(Size availableSize)
{
BuildSpanGraph();
// 频繁增删Children子元素会出现卡顿现象！
// Children = _rows + _recycledRows
RowLayoutModel rowLayoutModel = GetRowLayoutModel();
int less = rowLayoutModel.Count - Children.Count;
if (less > 0)
{
for (int i = 0; i < less; i++)
{
HeaderItem rowItem = new HeaderItem(this);
Children.Add(rowItem);
_recycledRows.Add(rowItem);
}
}
// 先回收不可见行
List <HeaderItem> rows = _rows.Values.ToList();
foreach (var rowItem in rows)
{
RowLayout layout = rowLayoutModel.FindRow(rowItem.Row);
if (layout == null || layout.Height <= 0.0)
{
_recycledRows.Add(rowItem);
_rows.Remove(rowItem.Row);
rowItem.Row = -1;
}
}
double x = Location.X;
double y = Location.Y;
double maxWidth = 0.0;
foreach (RowLayout layout in rowLayoutModel)
{
if (layout.Height <= 0.0)
{
continue;
}
bool updateAllCell = false;
HeaderItem rowItem = null;
if (!_rows.TryGetValue(layout.Row, out rowItem))
{
// 重新利用回收的行
rowItem = _recycledRows[0];
_recycledRows.RemoveAt(0);
rowItem.Row = layout.Row;
_rows.Add(layout.Row, rowItem);
updateAllCell = true;
}
rowItem.UpdateChildren(updateAllCell);
int z = rowItem.ContainsSpanCell ? _spanRowZIndexBase + rowItem.Row : _normalZIndexBase + rowItem.Row;
z = z % 0x7ffe;
Canvas.SetZIndex(rowItem, z);
rowItem.Location = new Point(x, y);
// 测量尺寸足够大，否则当单元格占多行时在uno上只绘一行！
rowItem.Measure(availableSize);
y += layout.Height;
maxWidth = Math.Max(maxWidth, rowItem.DesiredSize.Width);
}
// 测量回收的行
if (_recycledRows.Count > 0)
{
foreach (var rowItem in _recycledRows)
{
rowItem.Measure(_szEmpty);
}
}
return(new Size(maxWidth + Location.X, y));
}
public RowHeaderCell(HeaderItem p_rowItem)
: base(p_rowItem)
{
}
public ColHeaderCell(HeaderItem p_rowItem)
: base(p_rowItem)
{
}