PathNode.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / wpf / src / Framework / MS / Internal / Annotations / Anchoring / PathNode.cs / 1305600 / PathNode.cs
                        

                        
                            #pragma warning disable 1634, 1691 
//------------------------------------------------------------------------------
//
// 
//    Copyright (C) Microsoft Corporation.  All rights reserved. 
// 
// 
// Description: 
//     PathNode represents a node in a path (a subset of the element tree).
//     PathNodes can have other PathNodes as children.  Each refers to a 
//     single element in the element tree.
//     Spec: http://team/sites/ag/Specifications/Anchoring%20Namespace%20Spec.doc
//
// History: 
//  01/01/2003: magedz: Created - based on architectural discussions and design
//                      by axelk, rruiz, magedz 
//  07/23/2003: rruiz:  Ported to WCP 
//  08/18/2003: rruiz:  Updated as per spec: made the class public.
// 
//-----------------------------------------------------------------------------
using System;
using System.Diagnostics;
using System.Collections; 
using System.ComponentModel;
using System.Windows; 
using System.Windows.Annotations; 
using System.Windows.Media;
using System.Windows.Markup; 
using MS.Utility;

namespace MS.Internal.Annotations.Anchoring
{ 
    /// 
    ///     PathNode represents a node in a path (a subset of the element tree). 
    ///     PathNodes can have other PathNodes as children.  Each refers to a 
    ///     single element in the element tree.
    ///  
    internal sealed class PathNode
    {
        //-----------------------------------------------------
        // 
        //  Constructors
        // 
        //----------------------------------------------------- 

        #region Constructors 

        /// 
        ///     Creates an instance of PathNode that refers to the specified tree node.
        ///  
        /// the tree node represented by this instance 
        /// node is null 
        internal PathNode(DependencyObject node) 
        {
            if (node == null) 
                throw new ArgumentNullException("node");

            _node = node;
        } 

        #endregion Constructors 
 
        //------------------------------------------------------
        // 
        //  Public Methods
        //
        //-----------------------------------------------------
 
        #region Public Methods
 
        ///  
        ///     Determines if obj is a PathNode and refers to the same tree node
        ///     as this instance. 
        /// 
        /// the Object to test for equality 
        /// true if obj refers to the same tree node as this instance 
        public override bool Equals(Object obj) 
        {
            PathNode otherNode = obj as PathNode; 
            if (otherNode == null) 
                return false;
 
            return _node.Equals(otherNode.Node);
        }

        ///  
        ///     Generates a hash value for this PathNode based on the tree node
        ///     it refers to. 
        ///  
        /// a hash value for this instance based on its tree node
        public override int GetHashCode() 
        {
            if (_node == null)
                return base.GetHashCode();
 
            return _node.GetHashCode();
        } 
 
        #endregion Public Methods
 
        //------------------------------------------------------
        //
        //  Public Operators
        // 
        //------------------------------------------------------
 
        //----------------------------------------------------- 
        //
        //  Public Events 
        //
        //------------------------------------------------------

        //----------------------------------------------------- 
        //
        //  Public Properties 
        // 
        //-----------------------------------------------------
 
        #region Public Properties

        /// 
        ///     Returns the tree node referred to by this instance of PathNode. 
        /// 
        /// the tree node referred to by this instance 
        public DependencyObject Node 
        {
            get { return _node; } 
        }

        /// 
        ///     Returns a list of PathNodes that are children of this instance. 
        ///     This set of children is a subset of the children of the tree node
        ///     referred to by this PathNode. 
        ///  
        /// list of PathNodes that are children of this instance
        public IList Children 
        {
            get
            {
                return _children; 
            }
        } 
 
        #endregion Public Properties
 
        //-----------------------------------------------------
        //
        //  Internal Methods
        // 
        //------------------------------------------------------
 
        #region Internal Methods 

        ///  
        ///     Builds a path of PathNodes representing the nodes between all of
        ///     the nodes and the root of the tree.
        /// 
        /// the instance referring to the root of the tree; its 
        /// children/descendants only include the nodes between the root and
        /// all of the nodes 
        /// nodes is null 
        internal static PathNode BuildPathForElements(ICollection nodes)
        { 
            if (nodes == null)
                throw new ArgumentNullException("nodes");

            PathNode firstPathNode = null; 
            foreach (DependencyObject node in nodes)
            { 
                PathNode branch = BuildPathForElement(node); 
                if (firstPathNode == null)
                    firstPathNode = branch; 
                else
                    AddBranchToPath(firstPathNode, branch);
            }
 
            // make all the children readonly so we do not need to
            // lock the PathNode when getting the children 
            if (firstPathNode != null) 
                firstPathNode.FreezeChildren();
 
            return firstPathNode;
        }

        #endregion Internal Methods 

        //----------------------------------------------------- 
        // 
        //  Internal Operators
        // 
        //------------------------------------------------------

        //------------------------------------------------------
        // 
        //  Internal Events
        // 
        //----------------------------------------------------- 

        //------------------------------------------------------ 
        //
        //  Internal Properties
        //
        //----------------------------------------------------- 

        #region Internal Properties 
 
        /// 
        /// Property used to point content tree root's to their 'parent'. 
        /// For instance, the root of a PageViewer's content tree would point
        /// to the DocumentPaginator that is holding on to the tree.
        /// 
#pragma warning suppress 7009 
        internal static readonly DependencyProperty HiddenParentProperty = DependencyProperty.RegisterAttached("HiddenParent", typeof(DependencyObject), typeof(PathNode));
 
        #endregion Internal Properties 

        //----------------------------------------------------- 
        //
        //  Private Methods
        //
        //----------------------------------------------------- 

        #region Private Methods 
 
        /// 
        ///     Get the parent of the passed in object. 
        /// 
        /// the node whose parent is requested
        /// the parent of this node where parent is defined to be the
        /// first FrameworkElement/FrameworkContentElemnt found walking up the 
        /// node's parent chain, with a preference for the visual tree vs the
        /// logical tree 
        internal static DependencyObject GetParent(DependencyObject node) 
        {
            Debug.Assert(node != null, "node can not be null"); 

            DependencyObject current = node;
            DependencyObject parent = null;
 
            while (true)
            { 
                // Try for hidden parent first above all others 
                parent = (DependencyObject)current.GetValue(PathNode.HiddenParentProperty);
 
                if (parent == null)
                {
                    // Try for Visual parent
                    Visual visual = current as Visual; 

                    if (visual != null) 
                    { 
                        // This is a Visual node, get parent
                        parent = VisualTreeHelper.GetParent(visual); 
                    }
                }

                if (parent == null) 
                {
                    // Try for Model parent 
                    parent = LogicalTreeHelper.GetParent(current); 
                }
 
                // Check if located a parent, if so, check if it's the correct type
                if ((parent == null) ||
                    FrameworkElement.DType.IsInstanceOfType(parent) ||
                    FrameworkContentElement.DType.IsInstanceOfType(parent)) 
                {
                    break; 
                } 

                // Parent found but not of correct type, continue 
                current = parent;
                parent = null;
            }
 
            return parent;
        } 
 
        /// 
        ///      Builds a path from an element to the root of its tree.  Every 
        ///      element in between the element and the root is added to the
        ///      path.
        /// 
        /// the element to build a path for 
        /// the PathNode instance referring to the root of the tree; its
        /// children/descendants only include the nodes between the root and 
        /// node 
        private static PathNode BuildPathForElement(DependencyObject node)
        { 
            Debug.Assert(node != null, "node can not be null");

            PathNode childNode = null;
            while (node != null) 
            {
                PathNode pathNode = new PathNode(node); 
 
                if (childNode != null)
                    pathNode.AddChild(childNode); 

                childNode = pathNode;

                // If we find a node that has the service set on it, we should stop 
                // after processing it.  For cases without a service like unit tests,
                // this node won't be found and we'll continue to the root. 
                if (node.ReadLocalValue(AnnotationService.ServiceProperty) != DependencyProperty.UnsetValue) 
                    break;
 
                node = PathNode.GetParent(node);
            }

            return childNode; 
        }
 
        ///  
        ///     Adds a branch to an existing path, removing any duplicate
        ///     nodes as necessary.  Assumes that both paths are full paths 
        ///     up to the root of the same tree.  If the paths are not full,
        ///     the method will give incorrect results.  If the paths are
        ///     full but belong to different trees (and therefore have
        ///     different roots) the method will throw. 
        /// 
        /// path to add branch to 
        /// branch to be added; should be a linear path 
        /// (no more than one child for any node)
        /// the path with branch having been added in and duplicate 
        /// nodes pruned
        private static PathNode AddBranchToPath(PathNode path, PathNode branch)
        {
            Debug.Assert(path != null, "path can not be null"); 
            Debug.Assert(branch != null, "branch can not be null");
 
            // The paths must be in the same tree and therefore have the 
            // same root.
            Debug.Assert(path.Node.Equals(branch.Node), "path.Node is not equal to branch.Node"); 

            PathNode fp = path;
            PathNode sp = branch;
 
            // Continue down
            while (fp.Node.Equals(sp.Node) && sp._children.Count > 0) 
            { 
                // if the firstpath component equals the second path component
                // then we try to find the second path child component 
                // inside the first path children
                bool found = false;
                PathNode branchNode = (PathNode)sp._children[0];
 
                foreach (PathNode fpn in fp._children)
                { 
                    if (fpn.Equals(branchNode)) 
                    {
                        // if we found one we keep moving along both the first path and the second path 
                        found = true;
                        sp = branchNode;
                        fp = fpn;
                        break; 
                    }
                } 
 
                if (found)
                    continue; 

                // if we can not find the second path child in the first
                // path child, we then just add the second path child
                // to the set of first path children 
                fp.AddChild(branchNode);
                break; 
            } 

            return path; 
        }

        private void AddChild(object child)
        { 
            _children.Add(child);
        } 
 
        /// 
        /// Once the node has been constructed via BuildPathForElements 
        /// we can not modify any more the childeren. We make the
        /// children trough the entire PathNode tree readonly
        /// 
        private void FreezeChildren() 
        {
            foreach (PathNode node in _children) 
            { 
                node.FreezeChildren();
            } 
            _children = ArrayList.ReadOnly(_children);
        }

        #endregion Private Methods 

        //------------------------------------------------------ 
        // 
        //  Private Fields
        // 
        //-----------------------------------------------------

        #region Private Fields
 
        // The element pointed to by this PathNode
        private DependencyObject    _node; 
 
        // The array of children of this PathNode
        private ArrayList           _children = new ArrayList(1); 

        #endregion Private Fields
    }
} 


// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.

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