CREATE TABLE [dbo].[tbTree] (   [ID] [int] IDENTITY (1, 1) NOT NULL , [Context] [nvarchar] (50) COLLATE Chinese_PRC_CI_AS NULL ,    [ParentID] [int] NULL ) ON [PRIMARY]

SET IDENTITY_INSERT tbtree ONinsert tbtree (ID,Context,ParentID)  values ( 1,'中国',0)insert tbtree (ID,Context,ParentID)  values ( 2,'北京',11)insert tbtree (ID,Context,ParentID)  values ( 3,'天津',11)insert tbtree (ID,Context,ParentID)  values ( 4,'河北省',1)insert tbtree (ID,Context,ParentID)  values ( 5,'广东省',1)insert tbtree (ID,Context,ParentID)  values ( 6,'广州',5)insert tbtree (ID,Context,ParentID)  values ( 7,'四川省',1)insert tbtree (ID,Context,ParentID)  values ( 8,'成都',7)insert tbtree (ID,Context,ParentID)  values ( 9,'深圳',5)insert tbtree (ID,Context,ParentID)  values ( 10,'石家庄',4)insert tbtree (ID,Context,ParentID)  values ( 11,'辽宁省',1)insert tbtree (ID,Context,ParentID)  values ( 12,'大连',11)insert tbtree (ID,Context,ParentID)  values ( 13,'上海',1)insert tbtree (ID,Context,ParentID)  values ( 14,'天河软件园',6)insert tbtree (ID,Context,ParentID)  values ( 15,'汕头',5)SET IDENTITY_INSERT tbtree off

    Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load        Dim ds As New DataSet()        Dim CN As New SqlConnection()        Try            '初始化连接字符串            CN.ConnectionString =             "data source=pmserver;initial catalog=Benchmark;persist security info=False;user id=sa;Password=sa;"            CN.Open()            Dim adp As SqlDataAdapter = New SqlDataAdapter("select * from tbTree", CN)            adp.Fill(ds)            Me.ViewState("ds") = ds        Catch ex As Exception#If DEBUG Then            Session("Error") = ex.ToString()            Response.Redirect("error.aspx")        '̀跳转程序的公共错误处理页面#End If        Finally            '关闭连接            CN.Close()        End Try        '调用递归函数，完成树形结构的生成        AddTree(0, Nothing)    End Sub

    '递归添加树的节点    Private Sub AddTree(ByVal ParentID As Integer, ByVal pNode As TreeNode)        Dim ds As DataSet        ds = Me.ViewState("ds")        Dim dvTree As New DataView()        dvTree = New DataView(ds.Tables(0))        '过滤ParentID,得到当前的所有子节点        dvTree.RowFilter = "PARENTID = " + ParentID.ToString

        Dim Row As DataRowView        For Each Row In dvTree            Dim Node As New TreeNode()            If pNode Is Nothing Then  '判断是否根节点                '添加根节点                Node.Text = Row("ConText").ToString()                TreeView1.Nodes.Add(Node)                Node.Expanded = True                '再次递归                AddTree(Int32.Parse(Row("ID").ToString()), Node)            Else                '̀添加当前节点的子节点                Node.Text = Row("ConText").ToString()                pNode.Nodes.Add(Node)                Node.Expanded = True                '再次递归                AddTree(Int32.Parse(Row("ID").ToString()), Node)            End If        Next    End Sub

using System;using System.Collections;using System.ComponentModel;using System.Data;using System.Drawing;using System.Web;using System.Web.SessionState;using System.Web.UI;using System.Web.UI.WebControls;using System.Web.UI.HtmlControls;using Microsoft.Web.UI.WebControls;using System.Data.SqlClient;namespace TreeCS{ ///   /// WebForm1 的摘要说明    ///   public class WebForm1 : System.Web.UI.Page    {     protected Microsoft.Web.UI.WebControls.TreeView TreeView1;

      private void Page_Load(object sender, System.EventArgs e)     {         // 定义数据库连接            SqlConnection CN = new SqlConnection();          try           {             //初始化连接字符串                CN.ConnectionString=             "data source=pmserver;initial catalog=Benchmark;persist security info=False;user id=sa;Password=sa;";              CN.Open();

              SqlDataAdapter adp = new SqlDataAdapter("select * from tbTree",CN);                DataSet ds=new DataSet();                adp.Fill(ds);             this.ViewState["ds"]=ds;           }         catch (Exception ex)          {             Session["Error"] = ex.ToString();              Response.Redirect("error.aspx");       //̀跳转程序的公共错误处理页面         }         finally           {             CN.Close();           }         //调用递归函数，完成树形结构的生成         AddTree(0, (TreeNode)null);       }

       //递归添加树的节点        public void AddTree(int ParentID,TreeNode pNode)      {         DataSet ds=(DataSet) this.ViewState["ds"];             DataView dvTree = new DataView(ds.Tables[0]);            //过滤ParentID,得到当前的所有子节点           dvTree.RowFilter =  "[PARENTID] = " + ParentID;

            foreach(DataRowView Row in dvTree)            {             TreeNode Node=new TreeNode() ;               if(pNode == null)               {    //添加根节点                  Node.Text = Row["ConText"].ToString();                 TreeView1.Nodes.Add(Node);                    Node.Expanded=true;                  AddTree(Int32.Parse(Row["ID"].ToString()), Node);    //再次递归             }                 else              {   //̀添加当前节点的子节点                 Node.Text = Row["ConText"].ToString();                 pNode.Nodes.Add(Node);                    Node.Expanded = true;                    AddTree(Int32.Parse(Row["ID"].ToString()),Node);     //再次递归             }         }                         }            

       #region Web Form Designer generated code      override protected void OnInit(EventArgs e)       {         //            // CODEGEN该调用是 ASP.NET Web 窗体设计器所必需的。         //            InitializeComponent();            base.OnInit(e);       }

       /// <summary>       ///设计器支持所需的方法 - 不要使用代码编辑器修改       /// 此方法的内容        /// </summary>      private void InitializeComponent()        {             this.Load += new System.EventHandler(this.Page_Load);

     }     #endregion    }}