internal void EnsureElementSize(
Size availableSize,
VirtualizingLayoutContext context,
double layoutItemWidth,
double layoutItemHeight,
UniformGridLayoutItemsStretch stretch,
Orientation orientation,
double minRowSpacing,
double minColumnSpacing,
int maxItemsPerLine)
{
if (maxItemsPerLine == 0)
{
maxItemsPerLine = 1;
}
if (context.ItemCount > 0)
{
// If the first element is realized we don't need to cache it or to get it from the context
var realizedElement = FlowAlgorithm.GetElementIfRealized(0);
if (realizedElement != null)
{
realizedElement.Measure(availableSize);
SetSize(realizedElement, layoutItemWidth, layoutItemHeight, availableSize, stretch, orientation, minRowSpacing, minColumnSpacing, maxItemsPerLine);
_cachedFirstElement = null;
}
else
{
if (_cachedFirstElement == null)
{
// we only cache if we aren't realizing it
_cachedFirstElement = context.GetOrCreateElementAt(
0,
ElementRealizationOptions.ForceCreate | ElementRealizationOptions.SuppressAutoRecycle); // expensive
}
_cachedFirstElement.Measure(availableSize);
SetSize(_cachedFirstElement, layoutItemWidth, layoutItemHeight, availableSize, stretch, orientation, minRowSpacing, minColumnSpacing, maxItemsPerLine);
// See if we can move ownership to the flow algorithm. If we can, we do not need a local cache.
bool added = FlowAlgorithm.TryAddElement0(_cachedFirstElement);
if (added)
{
_cachedFirstElement = null;
}
}
}
}
internal void EnsureElementSize(
Size availableSize,
VirtualizingLayoutContext context,
double layoutItemWidth,
double LayoutItemHeight,
UniformGridLayoutItemsStretch stretch,
Orientation orientation,
double minRowSpacing,
double minColumnSpacing)
{
if (context.ItemCount > 0)
{
// If the first element is realized we don't need to cache it or to get it from the context
var realizedElement = FlowAlgorithm.GetElementIfRealized(0);
if (realizedElement != null)
{
realizedElement.Measure(availableSize);
SetSize(realizedElement, layoutItemWidth, LayoutItemHeight, availableSize, stretch, orientation, minRowSpacing, minColumnSpacing);
_cachedFirstElement = null;
}
else
{
if (_cachedFirstElement == null)
{
// we only cache if we aren't realizing it
_cachedFirstElement = context.GetOrCreateElementAt(
0,
ElementRealizationOptions.ForceCreate | ElementRealizationOptions.SuppressAutoRecycle); // expensive
}
_cachedFirstElement.Measure(availableSize);
// This doesn't need to be done in the UWP version and I'm not sure why. If we
// don't do this here, and we receive a recycled element then it will be shown
// at its previous arrange point, but we don't want it shown at all until its
// arranged.
_cachedFirstElement.Arrange(new Rect(-10000.0, -10000.0, 0, 0));
SetSize(_cachedFirstElement, layoutItemWidth, LayoutItemHeight, availableSize, stretch, orientation, minRowSpacing, minColumnSpacing);
// See if we can move ownership to the flow algorithm. If we can, we do not need a local cache.
bool added = FlowAlgorithm.TryAddElement0(_cachedFirstElement);
if (added)
{
_cachedFirstElement = null;
}
}
}
}