protected void ApplyTemplate()
{
ReleaseVisualTree();
ControlTemplate template = Template ?? DefaultControlTemplate;
_visualTree = template(this);
// TODO: OnApplyTemplate
}
public static Region GetRegion(UiElement descendant)
{
while (descendant != null && !(descendant is Region))
{
descendant = descendant.Parent;
}
return (Region)descendant;
}
public Generation(object item, UiElement container)
{
Container = container;
Item = item;
}
public void ReleaseContainer(UiElement container)
{
for (int i = _generations.Count - 1; i >= 0; i--)
{
if (((Generation)_generations[i]).Container == container)
{
_generations.RemoveAt(i);
break;
}
}
}
public object GetItemForContainer(UiElement container)
{
for (int i = _generations.Count - 1; i >= 0; i--)
{
Generation g = (Generation)_generations[i];
if (g.Container == container)
{
return g.Item;
}
}
return null;
}
public int GetIndexForContainer(UiElement container)
{
object item = GetItemForContainer(container);
if (item == null)
return -1;
return ((ArrayListExt) (object) _allItems()).BinarySearch(item, _comparer);
}
public int GetIndexForContainer(UiElement container)
{
object item = GetItemForContainer(container);
if (item == null)
return -1;
return _allItems.IndexOf(item);
}
protected void ReleaseVisualTree()
{
// TODO
_visualTree = null;
}
private void Synchronize(bool clear)
{
int available = GetAvailableItemCount();
bool changed = false;
if (_scroller != null)
{
if (clear || (available == 0))
{
if (_itemContainerGenerator != null)
{
_desiredFirstItem = _itemContainerGenerator.GetIndexForContainer(_firstItemContainer);
if (_desiredFirstItem < 0)
{
_desiredFirstItem = _firstItem;
}
}
for (int i = Math.Max(_firstRealizedItem, 0); i <= _lastRealizedItem; i++)
{
ReleaseContainer(i);
changed = true;
}
_firstItem = -1;
_firstItemContainer = null;
_lastItem = -1;
_firstRealizedItem = -1;
_lastRealizedItem = -1;
}
if (available > 0)
{
_content.Height(available*_fixedItemHeight);
_desiredFirstItem = Math.Max(0, Math.Min(_desiredFirstItem, GetAvailableItemCount()));
if (_desiredFirstItem != _firstItem)
{
changed = true;
}
int firstRequired = _desiredFirstItem;
int viewSize = _scroller.GetInnerHeight();
double buffer = viewSize / (double)_fixedItemHeight;
int usableBuffer = Math.Floor(buffer);
int lastRequired = firstRequired + usableBuffer - 1;
if (lastRequired > available - 1)
{
int overshot = lastRequired - available + 1;
firstRequired = Math.Max(firstRequired - overshot, 0);
lastRequired = available - 1;
}
int firstAllowed = firstRequired - 2;
int lastAllowed = lastRequired + 2;
_firstItem = firstRequired;
_desiredFirstItem = _firstItem;
_firstItemContainer = _itemContainerGenerator.GetContainerForIndex(_firstItem);
_lastItem = lastRequired;
if (buffer - usableBuffer > 0)
{
lastRequired = Math.Min(lastRequired + 1, available - 1);
}
ShowScrollbar((_firstItem > 0) || (_viewportLines < available));
int layoutWidth = _content.GetInnerWidth();
// add any missing elements
for (int i = firstRequired; i <= lastRequired; i++)
{
if (_realizedItems[i] == null)
{
changed = true;
UiElement item = _itemContainerGenerator.GenerateContainer(i);
_realizedItems[i] = item;
item.Parent = this;
item.Measure(new Size(layoutWidth, _fixedItemHeight));
AxisArrangement v = ArrangeAxis(item.YAxis, item.MeasuredSize.Height, _fixedItemHeight);
v.Position += i * _fixedItemHeight;
item.Arrange(ArrangeAxis(item.XAxis, item.MeasuredSize.Width, _content.GetInnerWidth()),
v, _content[0]);
}
}
// show the new items
_content.CSS("top", (-firstRequired * _fixedItemHeight) + "px");
// remove any unnecessary elements)
for (int i = Math.Max(_firstRealizedItem, 0); i < firstAllowed; i++)
{
ReleaseContainer(i);
}
for (int i = lastAllowed + 1; i <= _lastRealizedItem; i++)
{
ReleaseContainer(i);
}
_firstRealizedItem = Math.Min(firstRequired, Math.Max(firstAllowed, _firstRealizedItem));
_lastRealizedItem = Math.Max(lastRequired, Math.Min(lastAllowed, _lastRealizedItem));
}
else
{
ShowScrollbar(false);
}
}
if (changed && Changed != null)
{
Changed();
}
}