1 using System;
 2 using System.Collections.Generic;
 3 using System.Linq;
 4 using System.Text;
 5 using System.Threading.Tasks;
 6 using MySql.Data.MySqlClient;
 7 using System.Data;
 8 namespace ChinaRegionTreeView
 9 {　　//连接数据库的类
10     class ConnectDB
11     {　　　　
12         private static String mysqlcon = "database=chinaregiondb;Password=1111;User ID=root;server=localhost";
13         private  MySqlConnection mysqlCon;
14         private DataSet ds;
15         MySqlDataAdapter mysqlAdapter = new MySqlDataAdapter();
16 
17         public DataSet Connect()
18         {
19             string sqlStr = "select * from chinaregiondb.tb_prov_city_area_street";
20             mysqlAdapter = new MySqlDataAdapter(sqlStr, mysqlcon);
21             ds = new DataSet();
22             mysqlAdapter.Fill(ds);
23             return ds;
24         }
25     }
26 }

 1 public void TreeViewBind(DataTable dt,TreeNode parentNode,string parentID)
 2         {
 3             DataRow[] rows = dt.Select(string.Format("parentID={0}", parentID));
 4             foreach (DataRow row in rows)
 5             {
 6                 TreeNode node=new TreeNode(){
 7                     Text=row["name"].ToString()
 8                 };
 9                 TreeViewBind(dt, node, row["code"].ToString());
10                 if (parentNode == null)
11                 {
12                     treeView1.Nodes.Add(node);
13                 }
14                 else
15                 {
16                     parentNode.Nodes.Add(node);
17                 }
18             }
19         }

1 private void button2_Click(object sender, EventArgs e)
2         {
3             treeView1.Nodes.Clear();
4             ConnectDB conDB = new ConnectDB();
5             dataGridView1.DataSource = conDB.Connect().Tables[0];
6             TreeViewBind(conDB.Connect().Tables[0],null,"0");
7         }