form1

public void treeView()        {            //  datatable 定义变量接收 传归来的值            DataTable Father = new BuMenDA().ConSql();            //查询出来的的结果不可能为空 for循环一条条查出来            for (int a = 0; a <= Father.Rows.Count; a++)            {
    // 定义新的节点接a行的 Name列                 TreeNode fatherNode = new TreeNode(Father.Rows[a]["Name"].ToString());                //给节点添加数据源                fatherNode.Tag = Father.Rows[a]["Name"].ToString();                // 绑定节点的Name值  Code  以便以后使用                fatherNode.Name = Father.Rows[a]["Code"].ToString();                treeView1.Nodes.Add(fatherNode);                //添加父节点                //根据节点的  Name 查询另一个表的数据                DataTable child = new BuMenDA().ConSql1(int.Parse(fatherNode.Name));             //再次循环                for (int b = 0; b < child.Rows.Count; b++)                {                    //同上  建立新的节点接收传过来值                    TreeNode ChildNode = new TreeNode(child.Rows[b]["Name"].ToString());                    //绑定数据源                    ChildNode.Tag = child;                    //在添加父节点的基础上添加子节点                    fatherNode.Nodes.Add(ChildNode);                }                         }        }           private void Form1_Load(object sender, EventArgs e)        {            treeView();        }

UseDA

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;using System.Data.SqlClient;using System.Data.Sql;using System.Data;namespace ListViewAdd.UseDA{  class BuMenDA    {      private string conn()      {          return "Server=.;Database=BuMen;User ID=sa;Password=123";      }      //查询第一个表的数据      public DataTable ConSql()      {          string sql = "select * from BuMenShow";          SqlConnection MyCon = new SqlConnection(conn());          MyCon.Open();          SqlDataAdapter myda = new SqlDataAdapter(sql, conn());          DataSet MD = new DataSet();          myda.Fill(MD);          return MD.Tables[0];      }      //查询第二个表的数据      public DataTable ConSql1(int Code)      {          string sql = "select * from Member  where MemCode =" + Code;          SqlConnection MyCon = new SqlConnection(conn());          MyCon.Open();          SqlDataAdapter myda = new SqlDataAdapter(sql, conn());          DataSet MD = new DataSet();          myda.Fill(MD);          return MD.Tables[0];      }    }}