private static bool ShouldIgnore(ScrollTraceOp op, ScrollTracingInfo sti)
{
return (op == ScrollTraceOp.NoOp);
}
private void AddTrace(VirtualizingStackPanel vsp, ScrollTraceOp op, ScrollTracingInfo sti, params object[] args)
{
ScrollTraceRecord record = new ScrollTraceRecord(op, vsp, sti.Depth, sti.ItemIndex, _depth, BuildDetail(args));
_traceList.Add(record);
switch (op)
{
default:
break;
case ScrollTraceOp.BeginMeasure:
Push();
break;
case ScrollTraceOp.EndMeasure:
Pop(record);
record.Snapshot = vsp.TakeSnapshot();
Flush(sti.Depth);
break;
case ScrollTraceOp.BeginArrange:
Push();
break;
case ScrollTraceOp.EndArrange:
Pop(record);
record.Snapshot = vsp.TakeSnapshot();
Flush(sti.Depth);
break;
case ScrollTraceOp.BSetAnchor:
Push();
break;
case ScrollTraceOp.ESetAnchor:
Pop(record);
break;
case ScrollTraceOp.BOnAnchor:
Push();
break;
case ScrollTraceOp.ROnAnchor:
Pop(record);
break;
case ScrollTraceOp.SOnAnchor:
Pop();
break;
case ScrollTraceOp.EOnAnchor:
Pop(record);
break;
case ScrollTraceOp.RecycleChildren:
case ScrollTraceOp.RemoveChildren:
record.RevirtualizedChildren = args[2] as List<String>;
break;
}
if (_flushDepth < 0)
{
Flush(_flushDepth);
}
}
internal static void ConfigureTracing(VirtualizingStackPanel vsp,
DependencyObject itemsOwner,
object parentItem,
ItemsControl itemsControl)
{
Debug.Assert(!IsConfigured(vsp));
ScrollTracer tracer = null;
if (itemsControl.Name == _targetName)
{
SetTarget(itemsControl, overwriteExistingTarget:false);
}
ScrollTracingInfo sti = _nullInfo; // default - do nothing
if (parentItem == vsp)
{
// top level VSP
if (itemsOwner == _target)
{
tracer = new ScrollTracer(itemsControl, vsp);
}
if (tracer != null)
{
sti = new ScrollTracingInfo(tracer, 0, itemsOwner as FrameworkElement, null, null, 0);
}
}
else
{
// inner VSP
VirtualizingStackPanel parent = VisualTreeHelper.GetParent(itemsOwner) as VirtualizingStackPanel;
if (parent != null)
{
ScrollTracingInfo parentInfo = ScrollTracingInfoField.GetValue(parent);
if (parentInfo != null)
{
tracer = parentInfo.ScrollTracer;
if (tracer != null)
{
ItemContainerGenerator generator = parent.ItemContainerGenerator as ItemContainerGenerator;
int itemIndex = (generator != null) ? generator.IndexFromContainer(itemsOwner, returnLocalIndex:true) : -1;
sti = new ScrollTracingInfo(tracer, parentInfo.Depth + 1, itemsOwner as FrameworkElement, parent, parentItem, itemIndex);
}
}
}
}
ScrollTracingInfoField.SetValue(vsp, sti);
}
