动态生成TreeView方法（二）

这次是用递归的方法实现，我想大家都知道怎么做吧，就不多说了，

还是不建议用递归，数据量大了会映响速度，动态生成TreeView方法（一）是我比较喜欢的方法

看一下效果图

前台代码：

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="TreeViewPageTwo.aspx.cs" Inherits="WebApplication3.TreeViewPageTwo" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:TreeView id="tv_Method" runat="server">
        
        </asp:TreeView>
    </div>
    </form>
</body>
</html>

后台代码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
namespace WebApplication3
{
    public partial class TreeViewPageTwo : System.Web.UI.Page
    {
        private DataTable da = new DataTable(); 
        protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                da = CreateTable();
                CreateNode();
            }
            
        }

        //创建父节点
        public void CreateNode()
        {
            DataRow[] rows = da.Select("parentID=0");//取出树的根节点
            if (rows.Length > 0)
            {
                foreach (DataRow row in rows)
                {
                    TreeNode root = new TreeNode();//添加一个节点
                    root.Value = row["MenuID"].ToString();
                    root.Text = row["MenuName"].ToString();
                    root.Expanded = false;
                    root.SelectAction = TreeNodeSelectAction.Expand;
                    tv_Method.Nodes.Add(root);
                    CreateChildNode(root, da);//调用添加子节点
                }
            }
            else
            {
                TreeNode root = new TreeNode();//添加一个节点
                root.Value = "为空";
                root.Text ="为空";
                root.Expanded = false;
                root.SelectAction = TreeNodeSelectAction.Expand;
                tv_Method.Nodes.Add(root);
            }
        }

        //创建孩子节点
        public void CreateChildNode(TreeNode parentNode, DataTable dt)
        {
            //获取父亲节点下面的所有子节点
            DataRow[] rows = dt.Select("parentID=" + parentNode.Value);
            if (rows.Length > 0)
            {
                foreach (DataRow row in rows)
                {
                    TreeNode node = new TreeNode();
                    node.Value = row["MenuID"].ToString();
                    node.Text = row["MenuName"].ToString();
                    node.Expanded = false;
                    node.SelectAction = TreeNodeSelectAction.Expand;
                    parentNode.ChildNodes.Add(node);
                    //递归调用添加子节点
                    CreateChildNode(node, dt);
                }
            }
        }
       
        //创建Table
        public DataTable CreateTable()
        {
            DataTable dt = new DataTable();
            dt.Columns.Add("MenuID", Type.GetType("System.Int32"));
            dt.Columns.Add("parentID", Type.GetType("System.Int32"));
            dt.Columns.Add("MenuName", Type.GetType("System.String"));

            DataRow dr = dt.NewRow();
            dr["MenuID"] = 1;
            dr["parentID"] = 0;
            dr["MenuName"] = "中国";
            dt.Rows.Add(dr);
            dr = dt.NewRow();
            dr["MenuID"] = 2;
            dr["parentID"] = 0;
            dr["MenuName"] = "日本";
            dt.Rows.Add(dr);
            dr = dt.NewRow();
            dr["MenuID"] = 3;
            dr["parentID"] = 0;
            dr["MenuName"] = "美国";
            dt.Rows.Add(dr);
            dr = dt.NewRow();
            dr["MenuID"] = 4;
            dr["parentID"] = 1;
            dr["MenuName"] = "朝阳区";
            dt.Rows.Add(dr);
            dr = dt.NewRow();
            dr["MenuID"] = 5;
            dr["parentID"] = 1;
            dr["MenuName"] = "海淀区";
            dt.Rows.Add(dr);



            return dt;
        }
 


    }
}