View Code    /// <summary>    /// 二叉树节点    /// </summary>    /// <typeparam name="T">The item type</typeparam>    public class BinaryTreeNode<T>    {      #region Constructors      /// <summary>      /// 二叉树节点      /// </summary>      public BinaryTreeNode()      {      }      /// <summary>      /// 二叉树节点      /// </summary>      /// <param name="value">节点中的值</param>      public BinaryTreeNode(T value)      {        this.Value = value;      }      /// <summary>      /// 二叉树节点      /// </summary>      /// <param name="value">节点中的值</param>      /// <param name="parent">节点的父节点</param>      public BinaryTreeNode(T value, BinaryTreeNode<T> parent)      {        this.Value = value;        this.Parent = parent;      }      /// <summary>      /// 二叉树节点      /// </summary>      /// <param name="value">节点中的值</param>      /// <param name="parent">节点的父节点</param>      /// <param name="left">节点的左节点</param>      /// <param name="right">节点的右节点</param>      public BinaryTreeNode(T value,        BinaryTreeNode<T> parent,        BinaryTreeNode<T> left,        BinaryTreeNode<T> right)      {        this.Value = value;        this.Right = right;        this.Left = left;        this.Parent = parent;      }      #endregion      #region Properties      /// <summary>      /// 节点值      /// </summary>      public T Value { get; set; }      /// <summary>      /// 父节点      /// </summary>      public BinaryTreeNode<T> Parent { get; set; }      /// <summary>      /// 左节点      /// </summary>      public BinaryTreeNode<T> Left { get; set; }      /// <summary>      /// 右节点      /// </summary>      public BinaryTreeNode<T> Right { get; set; }      /// <summary>      /// 是否为根节点      /// </summary>      public bool IsRoot { get { return Parent == null; } }      /// <summary>      /// 是否为叶子节点      /// </summary>      public bool IsLeaf { get { return Left == null && Right == null; } }      /// <summary>      /// 是否为可访问的      /// </summary>      internal bool Visited { get; set; }      #endregion      #region Public Overridden Functions      /// <summary>      /// Returns a <see cref="System.String"/> that represents this instance.      /// </summary>      /// <returns>      /// A <see cref="System.String"/> that represents this instance.      /// </returns>      public override string ToString()      {        return Value.ToString();      }      #endregion    }

View Code    /// <summary>    /// 二叉树    /// </summary>    /// <typeparam name="T">二叉树中节点内容类型</typeparam>    [SuppressMessage("Microsoft.Naming", "CA1710:IdentifiersShouldHaveCorrectSuffix")]    public class BinaryTree<T> : ICollection<T>, IEnumerable<T> where T : IComparable<T>    {      #region Constructor      /// <summary>      /// 二叉树      /// </summary>      public BinaryTree()      {        NumberOfNodes = 0;      }      /// <summary>      /// 二叉树      /// </summary>      /// <param name="root">二叉树根节点</param>      public BinaryTree(BinaryTreeNode<T> root)        : this()      {        this.Root = root;      }      #endregion      #region Properties      /// <summary>      /// 树的根节点      /// </summary>      public BinaryTreeNode<T> Root { get; set; }      /// <summary>      /// 树中节点的数量      /// </summary>      protected int NumberOfNodes { get; set; }      /// <summary>      /// 树是否为空      /// </summary>      public bool IsEmpty { get { return Root == null; } }      /// <summary>      /// 获取树中节点的最小值      /// </summary>      public T MinValue      {        get        {          if (IsEmpty)            return default(T);          BinaryTreeNode<T> minNode = Root;          while (minNode.Left != null)            minNode = minNode.Left;          return minNode.Value;        }      }      /// <summary>      /// 获取树中节点的最大值      /// </summary>      public T MaxValue      {        get        {          if (IsEmpty)            return default(T);          BinaryTreeNode<T> maxNode = Root;          while (maxNode.Right != null)            maxNode = maxNode.Right;          return maxNode.Value;        }      }      #endregion      #region IEnumerable<T> Members      /// <summary>      /// Returns an enumerator that iterates through the collection.      /// </summary>      /// <returns>      /// A <see cref="T:System.Collections.Generic.IEnumerator`1"></see>      /// that can be used to iterate through the collection.      /// </returns>      public IEnumerator<T> GetEnumerator()      {        foreach (BinaryTreeNode<T> node in Traverse(Root))        {          yield return node.Value;        }      }      #endregion      #region IEnumerable Members      /// <summary>      /// Returns an enumerator that iterates through a collection.      /// </summary>      /// <returns>      /// An <see cref="T:System.Collections.IEnumerator"/>      /// object that can be used to iterate through the collection.      /// </returns>      IEnumerator IEnumerable.GetEnumerator()      {        foreach (BinaryTreeNode<T> node in Traverse(Root))        {          yield return node.Value;        }      }      #endregion      #region ICollection<T> Members      /// <summary>      /// 新增节点      /// </summary>      /// <param name="item">The object to add to the      /// <see cref="T:System.Collections.Generic.ICollection`1"></see>.</param>      /// <exception cref="T:System.NotSupportedException">The      /// <see cref="T:System.Collections.Generic.ICollection`1"></see>      /// is read-only.</exception>      public void Add(T item)      {        if (Root == null)        {          Root = new BinaryTreeNode<T>(item);          ++NumberOfNodes;        }        else        {          Insert(item);        }      }      /// <summary>      /// 清除树      /// </summary>      public void Clear()      {        Root = null;      }      /// <summary>      /// 树中是否包含此节点      /// </summary>      /// <param name="item">The object to locate in the      /// <see cref="T:System.Collections.Generic.ICollection`1"></see>.</param>      /// <returns>      /// true if item is found in the      /// <see cref="T:System.Collections.Generic.ICollection`1"></see>; otherwise, false.      /// </returns>      public bool Contains(T item)      {        if (IsEmpty)          return false;        BinaryTreeNode<T> currentNode = Root;        while (currentNode != null)        {          int comparedValue = currentNode.Value.CompareTo(item);          if (comparedValue == 0)            return true;          else if (comparedValue < 0)            currentNode = currentNode.Left;          else            currentNode = currentNode.Right;        }        return false;      }      /// <summary>      /// 将树中节点拷贝至目标数组      /// </summary>      /// <param name="array">The array.</param>      /// <param name="arrayIndex">Index of the array.</param>      public void CopyTo(T[] array, int arrayIndex)      {        T[] tempArray = new T[NumberOfNodes];        int counter = 0;        foreach (T value in this)        {          tempArray[counter] = value;          ++counter;        }        Array.Copy(tempArray, 0, array, arrayIndex, Count);      }      /// <summary>      /// 树中节点的数量      /// </summary>      public int Count      {        get { return NumberOfNodes; }      }      /// <summary>      /// 树是否为只读      /// </summary>      public bool IsReadOnly      {        get { return false; }      }      /// <summary>      /// 移除节点      /// </summary>      /// <param name="item">节点值</param>      /// <returns>是否移除成功</returns>      public bool Remove(T item)      {        BinaryTreeNode<T> node = Find(item);        if (node == null)          return false;        List<T> values = new List<T>();        foreach (BinaryTreeNode<T> l in Traverse(node.Left))        {          values.Add(l.Value);        }        foreach (BinaryTreeNode<T> r in Traverse(node.Right))        {          values.Add(r.Value);        }        if (node.Parent.Left == node)        {          node.Parent.Left = null;        }        else        {          node.Parent.Right = null;        }        node.Parent = null;        foreach (T v in values)        {          this.Add(v);        }        return true;      }      #endregion      #region Private Functions      /// <summary>      /// 查找指定值的节点      /// </summary>      /// <param name="value">指定值</param>      /// <returns>      /// 指定值的节点      /// </returns>      protected BinaryTreeNode<T> Find(T value)      {        foreach (BinaryTreeNode<T> node in Traverse(Root))          if (node.Value.Equals(value))            return node;        return null;      }      /// <summary>      /// 遍历树      /// </summary>      /// <param name="node">遍历搜索的起始节点</param>      /// <returns>      /// The individual items from the tree      /// </returns>      [SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures")]      protected IEnumerable<BinaryTreeNode<T>> Traverse(BinaryTreeNode<T> node)      {        // 遍历左子树        if (node.Left != null)        {          foreach (BinaryTreeNode<T> left in Traverse(node.Left))            yield return left;        }        // 中序遍历二叉树, 顺序是 左子树，根，右子树        yield return node;        // 遍历右子树        if (node.Right != null)        {          foreach (BinaryTreeNode<T> right in Traverse(node.Right))            yield return right;        }      }      /// <summary>      /// 插入节点      /// </summary>      /// <param name="value">插入的节点值</param>      protected void Insert(T value)      {        // 从根节点开始比较        BinaryTreeNode<T> currentNode = Root;        while (true)        {          if (currentNode == null)            throw new InvalidProgramException("The current tree node cannot be null.");          // 比较当前节点与新节点的值          int comparedValue = currentNode.Value.CompareTo(value);          if (comparedValue < 0)          {            // 当前节点值小于新节点值            if (currentNode.Left == null)            {              currentNode.Left = new BinaryTreeNode<T>(value, currentNode);              ++NumberOfNodes;              return;            }            else            {              currentNode = currentNode.Left;            }          }          else if (comparedValue > 0)          {            // 当前节点值大于新节点值            if (currentNode.Right == null)            {              currentNode.Right = new BinaryTreeNode<T>(value, currentNode);              ++NumberOfNodes;              return;            }            else            {              currentNode = currentNode.Right;            }          }          else          {            // 当前节点值等于新节点值            currentNode = currentNode.Right;          }        }      }      #endregion    }

class Program    {      static void Main(string[] args)      {        Console.ForegroundColor = ConsoleColor.Green;        BinaryTree<string> tree = new BinaryTree<string>();        tree.Add("Dennis");        tree.Add("Gao");        tree.Add("Is");        tree.Add("A");        tree.Add("C#");        tree.Add("Programmer");        Console.WriteLine("Root Node Is : " + tree.Root.ToString());        Console.WriteLine();        foreach (var node in tree)        {          Console.WriteLine(node);        }        Console.ReadKey();      }    }