点滴积累【C#】---TreeView读取数据库

效果：

数据库：

思路：

利用for遍历，然后创建父节点，再根据父节点创建出子节点。

代码：

 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
     {
         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:父节点,
         //Grade:标识这是第几级节点,
         //Flag:标识是不是尾结点，1是 0 不是,
         //href:指向的链接
         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 <= )
                 {
                     tn.Text = "空";
                     tn.Value = "";
                     tn.NavigateUrl = "";
                     tn.Target = "";
                     tn.Expanded = false;
                     tn.SelectAction = TreeNodeSelectAction.SelectExpand;

                 }
                 else
                 {
                     for (int i = ; i < dt.Rows.Count; i++)
                     {
                         //创建父节点
                         if (dt.Rows[i]["Grade"].ToString() == "")
                         {
                             TreeNode node = new TreeNode();
                             node.Text = dt.Rows[i]["MenuName"].ToString();
                             node.Value = dt.Rows[i]["MenuID"].ToString();
                             if (dt.Rows[i]["Flag"].ToString() == "")
                             {
                                 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
                         {
                             //查找父节点
                             TreeNode ParentNod = (TreeNode)sl.GetByIndex(sl.IndexOfKey(dt.Rows[i]["ParentMenu"].ToString()));
                             //创建子节点
                             TreeNode tnChild = new TreeNode();
                             tnChild.Text = dt.Rows[i]["MenuName"].ToString();
                             tnChild.Value = dt.Rows[i]["MenuID"].ToString();
                             if (dt.Rows[i]["Flag"].ToString() == "")
                             {
                                 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;
             }
         }
     }
 }