public   class  RSS
     ... {
        public RSS()
        ...{
            this.items = new Dictionary<int, Item>();
        }

        private string title;

        public string Title
        ...{
            get ...{ return title; }
            set ...{ title = value; }
        }

        private Dictionary<int,Item> items;

        public Dictionary<int,Item> Items
        ...{
            get ...{ return items; }
            set ...{ items = value; }
        }

        public struct Item
        ...{
            private string title;

            public string Title
            ...{
                get ...{ return title; }
                set ...{ title = value; }
            }
            private string link;

            public string Link
            ...{
                get ...{ return link; }
                set ...{ link = value; }
            }
            private string pubdate;

            public string Pubdate
            ...{
                get ...{ return pubdate; }
                set ...{ pubdate = value; }
            }
            public Item(string t, string l, string p)
            ...{
                this.title = t;
                this.link = l;
                this.pubdate = p;
            }
        }
    }

public   partial   class  Form1 : Form
     ... {
        public Form1()
        ...{
            InitializeComponent();
        }

        private void buttonRead_Click(object sender, EventArgs e)
        ...{
            //读取RSS到doc
            XmlTextReader reader = new XmlTextReader(this.textBoxUrl.Text);
            XmlDocument doc = new XmlDocument();
            doc.Load(reader);
            //寻找rss结点
            XmlNode rss = FindNode(doc, "rss");
            //寻找channel结点
            XmlNode channel = FindNode(rss, "channel");
            RSS rssobj = new RSS();
            //把rss内容写入rssobj
            SetChannel(rssobj, channel);
            //将rssobj内容显示到treeview
            UpdateTreeView(rssobj);
        }

        private XmlNode FindNode(XmlNode node, string name)
        ...{
            foreach (XmlNode n in node.ChildNodes)
            ...{
                if (n.Name.Equals(name) && n.ChildNodes.Count > 0)
                    return n;
            }
            return null;
        }

        private void SetChannel(RSS rss, XmlNode channel)
        ...{
            foreach (XmlNode n in channel.ChildNodes)
            ...{
                if (n.Name.Equals("description"))
                ...{
                    rss.Title = n.InnerText;
                }
                else if (n.Name.Equals("item"))
                ...{
                    rss.Items.Add(rss.Items.Count, CreateItem(n));
                }
            }
        }

        private RSS.Item CreateItem(XmlNode node)
        ...{
            string title = "";
            string link = "";
            string pubdate = "";
            foreach (XmlNode n in node.ChildNodes)
            ...{
                switch (n.Name)
                ...{
                    case "title":
                        title = n.InnerText;
                        break;
                    case "link":
                        link = n.InnerText;
                        break;
                    case "pubDate":
                        pubdate = n.InnerText;
                        break;
                }
            }
            return new RSS.Item(title, link, pubdate);
        }

        private void UpdateTreeView(RSS rss)
        ...{
            this.treeViewRSS.BeginUpdate();
            this.treeViewRSS.Nodes.Clear();
            this.treeViewRSS.Nodes.Add(rss.Title);
            for(int i=0;i<rss.Items.Count;++i)
            ...{
                this.treeViewRSS.Nodes[0].Nodes.Add(rss.Items[i].Title);
                this.treeViewRSS.Nodes[0].Nodes[i].Tag = rss.Items[i].Link;
            }
            this.treeViewRSS.ExpandAll();
            this.treeViewRSS.EndUpdate();
        }
    }