Net学习日记_ADO.Net_2_练习(treeView)

主页面

数据库（基于之前的省市数据库）

主程序

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

namespace treeview1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        // 首先将所有数据读取出来，在进行递归排列
        List<Info> list = new List<Info>();
        private void Form1_Load(object sender, EventArgs e)
        {
            InitData();
            AddTree(0, null);
        }
        void InitData()
        {
            SqlConnection conn = new SqlConnection("server=PC201609230944\SQL2005;database=HeiMaBlog;user=sa;pwd=123456");
            SqlCommand cmd = new SqlCommand("select * from Area", conn);
            conn.Open();
            SqlDataReader dr = cmd.ExecuteReader();

            if (dr.HasRows)
            {
                while (dr.Read())
                {
                    Info nin = new Info() { Ar_id = dr.GetInt32(0), Ar_name = dr[1].ToString(), Ar_uid = dr.GetInt32(2) };
                    list.Add(nin);
                }
            }
        }

        // 递归
        // 父id和父节点
        // 省：父id = 0，父节点是trMain
        void AddTree(int pid, TreeNode pnod)
        {
            foreach (Info item in list)
            {
                if (item.Ar_uid == pid)
                {
                    // 新建一个节点，并且给节点赋值
                    TreeNode tnod = new TreeNode();
                    tnod.Text = item.Ar_name;
                    if (pnod == null)
                    {
                        // 父节点为null，添加到trMain
                        trMain.Nodes.Add(tnod);
                    }
                    else
                    {
                        //不是，就添加到父级点上
                        pnod.Nodes.Add(tnod);
                    }
                    AddTree(item.Ar_id, tnod);
                }
            }
        }

    }
}

辅助

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace treeview1
{
    class Info
    {
        /// <summary>
        /// 地区编号
        /// </summary>
        int ar_id;

        public int Ar_id
        {
            get { return ar_id; }
            set { ar_id = value; }
        }

        /// <summary>
        /// 地区名字
        /// </summary>
        string ar_name;

        public string Ar_name
        {
            get { return ar_name; }
            set { ar_name = value; }
        }

        /// <summary>
        /// 地区父级
        /// </summary>
        int ar_uid;

        public int Ar_uid
        {
            get { return ar_uid; }
            set { ar_uid = value; }
        }
    }
}