C# TreeView 읽기 데이터베이스 단순 인스턴스

아이디어:
for를 이용해서 부모 노드를 만들고 부모 노드에 따라 하위 노드를 만듭니다.
코드:

     using System; 
    
 using System.Collections.Generic; 
    
 using System.Linq; 
    
 using System.Web; 
    
 using System.Web.UI; 
    
 using System.Web.UI.WebControls; 
    
 using System.Data; 
    
 using System.Collections; 
    
 using System.Configuration; 
    
 using System.Data.SqlClient; 
    
 
 
    
  namespace TreeView
 
    
 {
     public partial class TreeView : System.Web.UI.Page
     { // www.jbxue.com
         string connection = ConfigurationManager.ConnectionStrings["SQLconnection"].ToString();
         protected void Page_Load(object sender, EventArgs e)
         {
             select();
             CreateTree();
         }
         DataSet ds = new DataSet();
         public DataSet DataS(string sql, string tablename)
         {
             SqlConnection con = new SqlConnection(connection);
             SqlDataAdapter sqlda = new SqlDataAdapter(sql, con);
             sqlda.Fill(ds, tablename);
             return ds;
         }
 
    
         //ParentMenu:   ,
         //Grade:         ,
         //Flag:        ，1  0   ,
         //href:     
         public void select()
         {
             string sql = "select * from treeview";
             ds = DataS(sql, "test");
         }
 
    
         public void CreateTree()
         {
             try
             {
                 DataTable dt = ds.Tables["test"];
                 SortedList sl = new SortedList();
                 TreeNode tn = new TreeNode();
                 if (dt.Rows.Count <= 0)
                 {
                     tn.Text = " ";
                     tn.Value = "";
                     tn.NavigateUrl = "";
                     tn.Target = "";
                     tn.Expanded = false;
                     tn.SelectAction = TreeNodeSelectAction.SelectExpand;
 
    
                 }
                 else
                 {
                     for (int i = 0; i < dt.Rows.Count; i++)
                     {
                         //     
                         if (dt.Rows[i]["Grade"].ToString() == "1")
                         {
                             TreeNode node = new TreeNode();
                             node.Text = dt.Rows[i]["MenuName"].ToString();
                             node.Value = dt.Rows[i]["MenuID"].ToString();
                             if (dt.Rows[i]["Flag"].ToString() == "1")
                             {
                                 node.NavigateUrl = dt.Rows[i]["href"].ToString();
                                 tn.Target = "_bank";
                             }
                             node.Expanded = false;
                             node.SelectAction = TreeNodeSelectAction.Expand;
                             sl.Add(node.Value, node);
                             tv_Method.Nodes.Add(node);
                         }
                         else
                         {
                             //     
                             TreeNode ParentNod = (TreeNode)sl.GetByIndex(sl.IndexOfKey(dt.Rows[i]["ParentMenu"].ToString()));
                             //     
                             TreeNode tnChild = new TreeNode();
                             tnChild.Text = dt.Rows[i]["MenuName"].ToString();
                             tnChild.Value = dt.Rows[i]["MenuID"].ToString();
                             if (dt.Rows[i]["Flag"].ToString() == "1")
                             {
                                 tnChild.NavigateUrl = dt.Rows[i]["href"].ToString();
                                 tnChild.Target = "_bank";
                             }
                             tnChild.Expanded = false;
                             tnChild.SelectAction = TreeNodeSelectAction.Expand;
                             sl.Add(tnChild.Value, tnChild);
                             ParentNod.ChildNodes.Add(tnChild);
                         }
                     }
                 }
             }
             catch (Exception ex)
             {
                 throw ex;
             }
         }
     }
 }