public void PhaseElement(UIElement element, VirtualizationInfo virtInfo)
{
var dataTemplateComponent = virtInfo.DataTemplateComponent;
var nextPhase = virtInfo.Phase;
bool shouldPhase = false;
if (nextPhase > 0)
{
if (dataTemplateComponent != null)
{
// Perf optimization: RecyclingElementFactory sets up the virtualization info so we don't need to update it here.
shouldPhase = true;
}
else
{
throw new InvalidOperationException("Phase was set on virtualization info, but dataTemplateComponent was not.");
}
}
else if (nextPhase == VirtualizationInfo.PhaseNotSpecified)
{
// If virtInfo.Phase is not specified, virtInfo.DataTemplateComponent cannot be valid.
global::System.Diagnostics.Debug.Assert(dataTemplateComponent == null);
// ItemsRepeater might be using a custom view generator in which case, virtInfo would not be bootstrapped.
// In this case, fallback to querying for the data template component and setup virtualization info now.
dataTemplateComponent = XamlBindingHelper.GetDataTemplateComponent(element);
if (dataTemplateComponent != null)
{
// Clear out old data.
dataTemplateComponent.Recycle();
nextPhase = VirtualizationInfo.PhaseReachedEnd;
var index = virtInfo.Index;
var data = m_owner.ItemsSourceView.GetAt(index);
// Run Phase 0
dataTemplateComponent.ProcessBindings(data, index, 0 /* currentPhase */, out nextPhase);
// Update phase on virtInfo. Set data and templateComponent only if x:Phase was used.
virtInfo.UpdatePhasingInfo(nextPhase, nextPhase > 0 ? data : null, nextPhase > 0 ? dataTemplateComponent : null);
shouldPhase = nextPhase > 0;
}
}
if (shouldPhase)
{
// Insert at the top since we remove from bottom during DoPhasedWorkCallback. This keeps the ordering of items
// the same as the order in which items are realized.
m_pendingElements.Insert(0, new ElementInfo(element, virtInfo));
RegisterForCallback();
}
}
protected override void RecycleElementCore(ElementFactoryRecycleArgs args)
{
XamlBindingHelper.GetDataTemplateComponent(args.Element).Recycle();
_recyclePool.PutElement(args.Element, key, args.Parent);
}
public static IDataTemplateComponent GetDataTemplateComponent(UIElement element) => XamlBindingHelper.GetDataTemplateComponent(element);
