C#使用TreeView控件实现的二叉树泛型节点类及其方法

// Form1.cs
namespace _135_8
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
 
        private void Form1_Load(object sender, EventArgs e)
        {
            treeView1!.Nodes.Add("根节点1");
            treeView1.Nodes[0].Nodes.Add("子节点1");
            treeView1.Nodes[0].Nodes.Add("子节点2");
            treeView1.Nodes.Add("根节点2");
        }
 
        private void TreeView1_AfterSelect(object? sender, TreeViewEventArgs e)
        {
            MessageBox.Show("你选择了节点: " + e.Node!.Text);
        }
    }
}

//Form1.Designer.cs
namespace _135_8
{
    partial class Form1
    {
        /// <summary>
        ///  Required designer variable.
        /// </summary>
        private System.ComponentModel.IContainer components = null;
 
        /// <summary>
        ///  Clean up any resources being used.
        /// </summary>
        /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
            {
                components.Dispose();
            }
            base.Dispose(disposing);
        }
 
        #region Windows Form Designer generated code
 
        /// <summary>
        ///  Required method for Designer support - do not modify
        ///  the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {
            treeView1 = new TreeView();
            SuspendLayout();
            // 
            // treeView1
            // 
            treeView1.Dock = DockStyle.Fill;
            treeView1.Location = new Point(0, 0);
            treeView1.Name = "treeView1";
            treeView1.Size = new Size(284, 181);
            treeView1.TabIndex = 0;
            treeView1.AfterSelect += TreeView1_AfterSelect;
            // 
            // Form1
            // 
            AutoScaleDimensions = new SizeF(7F, 17F);
            AutoScaleMode = AutoScaleMode.Font;
            ClientSize = new Size(284, 181);
            Controls.Add(treeView1);
            Name = "Form1";
            StartPosition = FormStartPosition.CenterScreen;
            Text = "Form1";
            Load += Form1_Load;
            ResumeLayout(false);
        }
 
        #endregion
        private TreeView treeView1;
    }
}

/// <summary>
/// 定义BinaryTreeNode<T>类
/// 泛型约束：可比较
/// </summary>
public class BinaryTreeNode<T>(T value) where T : IComparable<T>
{
    public T Value { get; set; } = value;
    public BinaryTreeNode<T>? Left { get; set; } = null;
    public BinaryTreeNode<T>? Right { get; set; } = null;
}
/// <summary>
/// 定义BinaryTree<T>类
/// 泛型约束：可比较
/// </summary>
public class BinaryTree<T> where T : IComparable<T>
{
    private BinaryTreeNode<T>? _root;
 
    public BinaryTree()
    {
        _root = null;
    }
 
    /// <summary>
    /// 添加节点的Add(T value)方法
    /// </summary>
    public void Add(T value)
    {
        _root = BinaryTree<T>.Add(value, _root!);
    }
 
    private static BinaryTreeNode<T> Add(T value, BinaryTreeNode<T> currentNode)
    {
        if (currentNode == null)
        {
            return new BinaryTreeNode<T>(value);
        }
 
        if (value.CompareTo(currentNode.Value) < 0)
        {
            currentNode.Left = BinaryTree<T>.Add(value, currentNode.Left!);
        }
        else if (value.CompareTo(currentNode.Value) > 0)
        {
            currentNode.Right = BinaryTree<T>.Add(value, currentNode.Right!);
        }
 
        return currentNode;
    }
 
    /// <summary>
    /// 将二叉树转换为 TreeView 控件的节点
    /// </summary>
    public void PopulateTreeView(TreeView treeView)
    {
        treeView.Nodes.Clear();
        if (_root != null)
        {
            treeView.Nodes.Add(BinaryTree<T>.CreateTreeNode(_root));
        }
    }
 
    private static TreeNode CreateTreeNode(BinaryTreeNode<T> node)
    {
        TreeNode treeNode = new(node.Value.ToString());
        if (node.Left != null)
        {
            treeNode.Nodes.Add(BinaryTree<T>.CreateTreeNode(node.Left));// 递归添加左子树
        }
        if (node.Right != null)
        {
            treeNode.Nodes.Add(BinaryTree<T>.CreateTreeNode(node.Right));// 递归添加右子树
        }
        return treeNode;
    }
}

 public partial class Form1 : Form
 {
     private BinaryTree<int>? binaryTree;
 
     public Form1()
     {
         InitializeComponent();
         //binaryTree = new BinaryTree<int>();
     }
 
     private void Form1_Load(object sender, EventArgs e)
     {
         // 初始化二叉树并添加节点
         binaryTree = new BinaryTree<int>();
         binaryTree.Add(5);
         binaryTree.Add(3);
         binaryTree.Add(7);
         binaryTree.Add(2);
         binaryTree.Add(4);
         binaryTree.Add(6);
         binaryTree.Add(8);
 
         treeView1.Refresh();
         // 将二叉树转换为 TreeView 控件的节点并显示
         binaryTree.PopulateTreeView(treeView1);
     }
 }