TreeChangeInfo.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / wpf / src / Framework / System / Windows / TreeChangeInfo.cs / 1305600 / TreeChangeInfo.cs
                        
                        
                            //---------------------------------------------------------------------------- 
//
// File: TreeChangeInfo.cs
//
// Description: 
//   This data-structure is used
//   1. As the data that is passed around by the DescendentsWalker 
//      during an AncestorChanged tree-walk. 
//
// Copyright (C) by Microsoft Corporation.  All rights reserved. 
//
//---------------------------------------------------------------------------

using System; 
using System.Collections.Generic;
using System.Diagnostics; 
using System.Windows.Media; 
using System.Windows.Controls;
using System.Windows.Documents; 
using MS.Internal;
using MS.Utility;

namespace System.Windows 
{
    ///  
    ///     This is the data that is passed through the DescendentsWalker 
    ///     during an AncestorChange tree-walk.
    ///  
    internal struct TreeChangeInfo
    {
        #region Properties
        public TreeChangeInfo(DependencyObject root, DependencyObject parent, bool isAddOperation) 
        {
            _rootOfChange = root; 
            _isAddOperation = isAddOperation; 
            _topmostCollapsedParentNode = null;
            _rootInheritableValues = null; 
            _inheritablePropertiesStack = null;
            _valueIndexer = 0;

            // Create the InheritableProperties cache for the parent 
            // and push it to start the stack ... we don't need to
            // pop this when we're done because we'll be throing the 
            // stack away at that point. 
            InheritablePropertiesStack.Push(CreateParentInheritableProperties(root, parent, isAddOperation));
        } 

        //
        //  This method
        //  1. Is called from AncestorChange InvalidateTree. 
        //  2. It is used to create the InheritableProperties on the given node.
        //  3. It also accumulates oldValues for the inheritable properties that are about to be invalidated 
        // 
        internal FrugalObjectList CreateParentInheritableProperties(
            DependencyObject                         d, 
            DependencyObject                         parent,
            bool                                     isAddOperation)
        {
            Debug.Assert(d != null, "Must have non-null current node"); 

            if (parent == null) 
            { 
                return new FrugalObjectList(0);
            } 

            DependencyObjectType treeObjDOT = d.DependencyObjectType;

            // See if we have a cached value. 
            EffectiveValueEntry[] parentEffectiveValues = null;
            uint parentEffectiveValuesCount = 0; 
            uint inheritablePropertiesCount = 0; 

            // If inheritable properties aren't cached on you then use the effective 
            // values cache on the parent to discover those inherited properties that
            // may need to be invalidated on the children nodes.
            if (!parent.IsSelfInheritanceParent)
            { 
                DependencyObject inheritanceParent = parent.InheritanceParent;
                if (inheritanceParent != null) 
                { 
                    parentEffectiveValues = inheritanceParent.EffectiveValues;
                    parentEffectiveValuesCount = inheritanceParent.EffectiveValuesCount; 
                    inheritablePropertiesCount = inheritanceParent.InheritableEffectiveValuesCount;
                }
            }
            else 
            {
                parentEffectiveValues = parent.EffectiveValues; 
                parentEffectiveValuesCount = parent.EffectiveValuesCount; 
                inheritablePropertiesCount = parent.InheritableEffectiveValuesCount;
            } 

            FrugalObjectList inheritableProperties = new FrugalObjectList((int) inheritablePropertiesCount);

            if (inheritablePropertiesCount == 0) 
            {
                return inheritableProperties; 
            } 

            _rootInheritableValues = new InheritablePropertyChangeInfo[(int) inheritablePropertiesCount]; 
            int inheritableIndex = 0;

            FrameworkObject foParent = new FrameworkObject(parent);
 
            for (uint i=0; i
        ///     This is a stack that is used during an AncestorChange operation. 
        ///     I holds the InheritableProperties cache on the parent nodes in
        ///     the tree in the order of traversal. The top of the stack holds
        ///     the cache for the immediate parent node.
        ///  
        internal Stack> InheritablePropertiesStack
        { 
            get 
            {
                if (_inheritablePropertiesStack == null) 
                {
                    _inheritablePropertiesStack = new Stack>(1);
                }
 
                return _inheritablePropertiesStack;
            } 
        } 

        ///  
        ///     When we enter a Visibility=Collapsed subtree, we remember that node
        ///     using this property. As we process the children of this collapsed
        ///     node, we see this property as non-null and know we're collapsed.
        ///     As we exit the subtree, this reference is nulled out which means 
        ///     we don't know whether we're in a collapsed tree and the optimizations
        ///     based on Visibility=Collapsed are not valid and should not be used. 
        ///  
        internal object TopmostCollapsedParentNode
        { 
            get { return _topmostCollapsedParentNode; }
            set { _topmostCollapsedParentNode = value; }
        }
 
        // Indicates if this is a add child tree operation
        internal bool IsAddOperation 
        { 
            get { return _isAddOperation; }
        } 

        // This is the element at the root of the sub-tree that had a parent change.
        internal DependencyObject Root
        { 
            get { return _rootOfChange; }
        } 
 
        #endregion Properties
 
        #region Data

        private Stack> _inheritablePropertiesStack;
        private object                                      _topmostCollapsedParentNode; 
        private bool                                        _isAddOperation;
        private DependencyObject                            _rootOfChange; 
        private InheritablePropertyChangeInfo[]             _rootInheritableValues; 
        private int                                         _valueIndexer;
 
        #endregion Data
    }
}
 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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TreeChangeInfo.cs source code in C# .NET

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