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using System;
using System.Collections;
using System.Diagnostics;
using System.Windows;
using System.Windows.Media;
using MS.Utility;
namespace System.Windows
{
/// <summary>
/// This is a base class to the DescendentsWalker. It is factored out so that
/// FrameworkContextData can store and retrieve it from context local storage
/// in a type agnostic manner.
/// </summary>
internal class DescendentsWalkerBase
{
#region Construction
protected DescendentsWalkerBase(TreeWalkPriority priority)
{
_startNode = null;
_priority = priority;
_recursionDepth = 0;
_nodes = new FrugalStructList<DependencyObject>();
}
#endregion Construction
internal bool WasVisited(DependencyObject d)
{
DependencyObject ancestor = d;
while ((ancestor != _startNode) && (ancestor != null))
{
DependencyObject logicalParent;
if (FrameworkElement.DType.IsInstanceOfType(ancestor))
{
FrameworkElement fe = ancestor as FrameworkElement;
logicalParent = fe.Parent;
// FrameworkElement
DependencyObject dependencyObjectParent = VisualTreeHelper.GetParent(fe);
if (dependencyObjectParent != null && logicalParent != null && dependencyObjectParent != logicalParent)
{
return _nodes.Contains(ancestor);
}
// Follow visual tree if not null otherwise we follow logical tree
if (dependencyObjectParent != null)
{
ancestor = dependencyObjectParent;
continue;
}
}
else
{
// FrameworkContentElement
FrameworkContentElement ancestorFCE = ancestor as FrameworkContentElement;
logicalParent = (ancestorFCE != null) ? ancestorFCE.Parent : null;
}
ancestor = logicalParent;
}
return (ancestor != null);
}
internal DependencyObject _startNode;
internal TreeWalkPriority _priority;
internal FrugalStructList<DependencyObject> _nodes;
internal int _recursionDepth;
}
/// <summary>
/// Enum specifying whether visual tree needs
/// to be travesed first or the logical tree
/// </summary>
internal enum TreeWalkPriority
{
/// <summary>
/// Traverse Logical Tree first
/// </summary>
LogicalTree,
/// <summary>
/// Traverse Visual Tree first
/// </summary>
VisualTree
}
}
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