public void ItemRemoved(int removed)
{
if (_realizedItem.ContainsKey(removed))
{
CollectionView.UnrealizeView(_realizedItem[removed].View);
_realizedItem.Remove(removed);
}
var items = _realizedItem.Keys.OrderBy(key => key);
foreach (var index in items)
{
if (index > removed)
{
_realizedItem[index - 1] = _realizedItem[index];
}
}
var last = items.LastOrDefault();
if (last > removed)
{
_realizedItem.Remove(last);
}
UpdateRemovedSize(removed);
_scrollCanvasSize = new Size(0, 0);
}
public void Reset()
{
foreach (var realizedItem in _realizedItem.Values.ToList())
{
CollectionView.UnrealizeView(realizedItem.View);
}
_realizedItem.Clear();
_scrollCanvasSize = new Size(0, 0);
}
public void ItemUpdated(int index)
{
if (_realizedItem.ContainsKey(index))
{
var bound = _realizedItem[index].View.Geometry;
CollectionView.UnrealizeView(_realizedItem[index].View);
var view = CollectionView.RealizeView(index);
_realizedItem[index].View = view;
view.Geometry = bound;
}
}
public void LayoutItems(Rect bound, bool force)
{
if (_allocatedSize.Width <= 0 || _allocatedSize.Height <= 0)
{
return;
}
// TODO : need to optimization. it was frequently called with similar bound value.
if (!ShouldRearrange(bound) && !force)
{
return;
}
_isLayouting = true;
_last = bound;
int padding = Span;
int startIndex = Math.Max(GetStartIndex(bound) - padding, 0);
int endIndex = Math.Min(GetEndIndex(bound) + padding, CollectionView.Count - 1);
foreach (var index in _realizedItem.Keys.ToList())
{
if (index < startIndex || index > endIndex)
{
CollectionView.UnrealizeView(_realizedItem[index].View);
_realizedItem.Remove(index);
}
}
var parent = CollectionView.ParentPosition;
for (int i = startIndex; i <= endIndex; i++)
{
EvasObject itemView;
if (!_realizedItem.ContainsKey(i))
{
var view = CollectionView.RealizeView(i);
_realizedItem[i] = new RealizedItem(view, i);
itemView = view;
}
else
{
itemView = _realizedItem[i].View;
}
var itemBound = GetItemBound(i);
itemBound.X += parent.X;
itemBound.Y += parent.Y;
itemView.Geometry = itemBound;
}
_isLayouting = false;
}