treeView

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Data.SqlClient;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        DataTable dt;
        private void Form1_Load(object sender, EventArgs e)
        {
            using(SqlConnection conn = new SqlConnection("server=.;uid=sa;pwd=sa;database=master"))
            {
                conn.Open();
                SqlDataAdapter sqlda = new SqlDataAdapter("select   *   from   CS_Info", conn);
                DataSet ds = new DataSet();
                sqlda.Fill(ds);
                dt= ds.Tables[0];
            }
            RootTree();
        }
       
        /// <summary>
        /// 添加根节点
        /// </summary>
        public void RootTree()
        {
            try
            {
                DataRow[] dr = dt.Select("pid=0");//找到所有的根节点信息
                DataTable dt_RootTree = dt.Clone();
                foreach(DataRow a in dr )
                {
                    dt_RootTree.ImportRow(a);
                }
                foreach (DataRow row in dt_RootTree.Rows)//添加根节点
                {
                    TreeNode nox = new TreeNode();
                    nox.Text = row["name"].ToString();
                    nox.Tag = Convert.ToInt32(row["id"].ToString());
                    nox.ExpandAll();

                    this.treeView1.Nodes.Add(nox);//往控件中添加根节点
                    ChildTree(nox);//添加子节点
                }
            }
            catch
            {
            }
        }


        /// <summary>
        /// 添加子节点
        /// </summary>
        /// <param name="nod">父节点</param>
        public void ChildTree(TreeNode nod)
        {
            try
            {
                DataRow[] dr = dt.Select("Pid="+nod.Tag);//根据传来的父节点的id【在添加父节点的方法中 把 id值 赋给了Tag】筛选，判断该根节点是否有字节点的存在
                DataTable dt_ChildTree = dt.Clone();
                foreach (DataRow a in dr)
                {
                    dt_ChildTree.ImportRow(a);//将该跟节点下的子节点信息 赋给dt_ChildTree
                }

                foreach (DataRow row in dt_ChildTree.Rows)//遍历dt_ChildTree 在该根节点上添加子节点
                {
                    TreeNode temp = new TreeNode();

                    temp.Text = row["name"].ToString();
                    temp.Tag = row["id"].ToString();
                    temp.ExpandAll();
                    nod.Nodes.Add(temp);
                }
            }
            catch
            {
            }
        }
        bool bl = true;//
//显示选中的节点信息  tag 和text值

 

 

         private void treeView1_BeforeSelect(object sender, TreeViewCancelEventArgs e)
        {
            if (!bl)
            {
                MessageBox.Show("Tag:" + e.Node.Tag.ToString() + " ; Text:" + e.Node.Text.ToString());
            }
            else
            {
                bl = false;
            }
        }

    }
}

 

create table CS_Info
(
id int,
name nvarchar(50),
Pid int
)

 

 

 

insert into CS_Info values(1,'数学',0)
insert into CS_Info values(2,'语文',0)
insert into CS_Info values(3,'英语',0)
insert into CS_Info values(4,'美术',0)
insert into CS_Info values(5,'音乐',0)


insert into CS_Info values(6,'函数',1)
insert into CS_Info values(7,'离散数学',1)
insert into CS_Info values(8,'概率论',1)
insert into CS_Info values(9,'线性代数',1)
insert into CS_Info values(10,'微积分',1)

insert into CS_Info values(11,'诗',2)
insert into CS_Info values(12,'词',2)
insert into CS_Info values(13,'歌',2)
insert into CS_Info values(14,'赋',2)
insert into CS_Info values(15,'论语',2)

insert into CS_Info values(16,'四级',3)
insert into CS_Info values(17,'托福',3)

insert into CS_Info values(18,'国画',4)
insert into CS_Info values(19,'水彩',4)

insert into CS_Info values(20,'美声',5)
insert into CS_Info values(21,'流行音乐',5)

insert into CS_Info values(22,'神学',0)