BNode类：

namespace binarysorttree.Tree {
    public class BNode<T> {
        public T data;
        public BNode<T> left;
        public BNode<T> right;

        public BNode(T data, BNode<T> left=null, BNode<T> right=null) {
            this.data = data;
            this.left = left;
            this.right = right;
        }
    }
}

BTree类：

using System;

namespace binarysorttree.Tree {
    public class BTree<T> {
        public BNode<T> root;

        public void preOrder() {
            Console.Write("先根遍历二叉树:");
            preOrder(this.root);
            Console.WriteLine();
        }
        public void preOrder(BNode<T> p) {
            if(p!=null) {
                Console.Write(p.data+" ");
                preOrder(p.left);
                preOrder(p.right);
            }
        }

        public void inOrder() {
            Console.Write("中根遍历二叉树:");
            inOrder(this.root);
            Console.WriteLine();
        }

        public void inOrder(BNode<T> p) {
            if(p!=null) {
                inOrder(p.left);
                Console.Write(p.data+" ");
                inOrder(p.right);
            }
        }

        public void postOrder() {
            Console.Write("后根遍历二叉树:");
            postOrder(this.root);
            Console.WriteLine();
        }

        public void postOrder(BNode<T> p) {
            if(p!=null) {
                postOrder(p.left);
                postOrder(p.right);
                Console.Write(p.data+" ");
            }
        }
    }
}

BinarySortTree类：

using System;

namespace binarysorttree.Tree {
    public class BinarySortTree<T> : BTree<T> where T:struct, IComparable<T>{
        
        public BinarySortTree():base() {
        }

        public BNode<T> search(T value) {
            BNode<T> p = this.root;
            while(p!=null && p.data.CompareTo(value)!=0) {
                if(value.CompareTo(p.data)<0) {
                    p=p.left;
                }else {
                    p=p.right;
                }
            }
            return p;
        }

    }
}

主程序类：

using System;
using binarysorttree.Tree;

namespace binarysorttree
{
    class Program
    {
        static void make(ref BinarySortTree<int> sortTree)
        {
            BNode<int> node12 = new BNode<int>(12, new BNode<int>(6), null);
            BNode<int> node18 = new BNode<int>(18, node12, new BNode<int>(36));
            BNode<int> node76 = new BNode<int>(76, null, new BNode<int>(81));
            BNode<int> node87 = new BNode<int>(87, node76, new BNode<int>(99));
            BNode<int> node66 = new BNode<int>(66, new BNode<int>(57), node87);
            BNode<int> node54 = new BNode<int>(54, node18, node66);
            sortTree.root = node54;
        }

        static void Main(string[] args)
        {
            BinarySortTree<int> bTree = new BinarySortTree<int>();
            Program.make(ref bTree);
            bTree.preOrder();
            BNode<int> node36 = bTree.search(36);
            if (node36 != null)
            {
                Console.WriteLine($"node36的数据为: {node36.data}");
            }
        }
    }
}

程序输出如下，

1.png