关于rss新闻阅读器，怎么添加不了子节点？

Question

//频道的基类using System;
using System.Collections.Generic;
using System.Text;namespace mynewsReader
{[Serializable]
   public abstract class FeedBase
    {
        public FeedBase() { }
        public FeedBase(string displayName,string url,string description,int clicks)
        {
            this.DisplayName = displayName;
            this.Url = url;
            this.Description = description;
            this.Clicks = clicks;
            //事例化存储文章的集合
            this.Articles = new Dictionary<string, Article>();
           
        }
        //存储文章列表的泛型集合
       private  Dictionary<string, Article> articles;        public  Dictionary<string, Article> Articles
        {
            get { return articles; }
            set { articles = value; }
        }
       //频道标题
        private string displayName;        public string DisplayName
        {
            get { return displayName; }
            set { displayName = value; }
        }
        //频道url;
        private string url;        public string Url
        {
            get { return url; }
            set { url = value; }
        }
        //频道描述
        private string description;        public string Description
        {
            get { return description; }
            set { description = value; }
        }
        //点击次数
        private int clicks;        public int Clicks
        {
            get { return clicks; }
            set { clicks = value; }
        }       public abstract bool FetchArticles();
    }
}//两个子类using System;
using System.Collections.Generic;
using System.Text;
using System.Xml;
using System.Net;
using System.Data.SqlClient;
using System.Windows.Forms;namespace mynewsReader
{
    [Serializable]
    class AtomFeed:FeedBase 
    {
          public AtomFeed() { }
        public AtomFeed(string title,string url):base(title ,url,"",0) { }
        public AtomFeed(string title,string url,string description):base(title ,url ,description ,0) { }
        public AtomFeed(string title, string url, string description, int clicks) : base(title, url, description, 0) { }
          //获取文章列表的方法
        public override bool FetchArticles() 
        {
            string filePath = "temp.atom";//文件路径
            try 
            {
                if (this.Articles == null)
                    this.Articles = new Dictionary<string, Article>();                this.Articles.Clear();
                //取得Atom格式文件
                WebClient myclient = new WebClient();
                myclient.DownloadFile(Url,filePath);
                //读取xml文档
                XmlDocument myxml = new XmlDocument();
                myxml.Load(filePath);
                //获取根节点
                XmlNode feedNode = myxml.DocumentElement;
                //外层按文章节点循环
                foreach (XmlNode node in feedNode.ChildNodes)
                {
                  if(node.Name =="entry")
                  {
                      Article atc = new Article();//实例化文章对象
                      //内层循环获取文章的详细信息
                      foreach (XmlNode subNode in node.ChildNodes)
                      {
                        switch (subNode .Name )
                        {
                            case "title":
                                atc.Title = subNode.InnerText;
                                break;
                            case "link":
                                atc.Url = subNode.Attributes["href"].Value.ToString();
                                break;
                        }
                      }
                      //将文章信息存入泛型集合中
                      this.Articles.Add(atc .Title ,atc );
                  }
                }
                Clicks++;
                return true;
            }
            catch(Exception ex)
            {
                MessageBox.Show(ex.Message );
                return false;
            }
        }
    }
}

Answer 1

using System;
using System.Collections.Generic;
using System.Text;
using System.Net;
using System.Xml;namespace mynewsReader
{
    [Serializable]
    class RssFeed:FeedBase 
    {
        public RssFeed() { }
        public RssFeed(string title,string url):base(title ,url,"",0) { }
        public RssFeed(string title,string url,string description):base(title ,url ,description ,0) { }
        public RssFeed(string title,string url,string description,int clicks):base(title ,url ,description ,0) { }        public override bool FetchArticles() 
        {
            string filePath = "temp.rss";
            try
            {
                if (this.Articles == null)
                    this.Articles = new Dictionary<string, Article>();
                Articles.Clear();
                WebClient webclient = new WebClient();
                webclient.DownloadFile(Url, filePath);
                XmlDocument myxml = new XmlDocument();
                myxml.Load(filePath);
                //获取父节点下的第一个字节点,定位channel节点
                XmlNode channel = myxml.DocumentElement.FirstChild;
                //定位item节点，外层循环channel
                foreach (XmlNode node in channel.ChildNodes)
                {
                    if (node.Name == "item")
                    {
                        Article atcl = new Article();
                        //内层循环item
                        foreach (XmlNode subnode in node.ChildNodes)
                        {
                            if (subnode.Name == "title")
                            {
                                atcl.Title = subnode.InnerText;
                            }
                            if (subnode.Name == "link")
                            {
                                atcl.Url = subnode.InnerText;
                            }
                        }
                        //将文章添加到文章列表
                        Articles.Add(atcl.Title, atcl);
                    }
                }
                return true;
            }
            catch (Exception ex)
            {                Console.WriteLine(ex.ToString ());
                return false;
            }
        }
    }
}

Answer 2

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms; namespace mynewsReader
{
    public partial class MyNewsReader : Form
    {
        public MyNewsReader()
        {
            InitializeComponent();
        }        private void MyNewsReader_Load(object sender, EventArgs e)
        {
            ProfileManager pm = new ProfileManager();
           //pm.profile.intialFeeds();
           // pm.save();
           // pm.Load();
            pm.ChannelReset();
            //遍历频道集合
            foreach (FeedBase feed in pm .profile .Feeds)
            {
                TreeNode feednode;
                //将一个频道加入节点
                feednode = treeView1.Nodes.Add(feed .DisplayName);
                feednode.Tag = feed;
            }
        }        private void treeview_afterSelect(object sender, TreeViewEventArgs e)
        {
            TreeNode n = this.treeView1.SelectedNode;
            if (n.Level == 1)
            {
                FeedBase f1 = (FeedBase)n.Tag;
                this.webBrowser1.Url = new Uri("http://rss.sina.com.cn/news/marquee/ddt.xml");
            }            if (n.Level != 0) return;
            FeedBase f = (FeedBase)n.Tag;            f.FetchArticles();
         
                    foreach (string title in f.Articles.Keys)
                    {
                        TreeNode nod;                        nod = n.Nodes.Add(title);
                        nod.BeginEdit();
                        //this.treeView1.SelectedNode.Nodes.Add(title,f.Articles[title].ToString());                    
                            }        }
             
    }
}红颜色的这段代码，点击哪个节点，即点哪个频道，相应地把该频道的所有文章标题作为他的子节点展示出来
但是就是出不来，文章集合里面也有数据，怎么添加不上子节点，我感觉这段代码好像很正确，看不出错在哪？希望高收指点