今天写了一个简单的新浪新闻RSS操作类库

今天，有位群友问我如何获新浪新闻列表相关问题，我想，用正则表达式网页中取显然既复杂又不一定准确，现在许多大型网站都有RSS集合，所以我就跟他说用RSS应该好办一些。

一年前我写过一个RSS阅读器，不过，打新浪相关的XML文件看了一下，发现RSS2.0 和一年前的不大一样了，但具体怎么处理，几句话也很难讲得清楚，所以，我干脆写了一个类库给他，直接调用。

类库不是很复杂，主要两个功能：

一、通过新浪的根频道XML在把所有频道的信息读出来，使用递归连同子节点也读取出来。

二、指定频道URL的XML文件来获取新闻信息。

首先，我们写两个类，一个用于保存新闻个息，另一个用于保存频道信息。

    /// <summary>
    /// 新闻记录实体
    /// </summary>
    [Serializable]
    public  class NewsItem
    {
        /// <summary>
        /// 新闻标题
        /// </summary>
        public string Title { get; set; }

        /// <summary>
        /// 新闻链接
        /// </summary>
        public string Link { get; set; }

        /// <summary>
        /// 作者
        /// </summary>
        public string Author { get; set; }

        /// <summary>
        /// 分类
        /// </summary>
        public string Category { get; set; }

        /// <summary>
        /// 发布时间
        /// </summary>
        public DateTime PubDate { get; set; }

        /// <summary>
        /// 描述
        /// </summary>
        public string Description { get; set; }

        /// <summary>
        /// 其它说明
        /// </summary>
        public string Comments { get; set; }
    }

    /// <summary>
    /// 新闻频道列表 
    /// </summary>
    [Serializable]
    public  class OutLine
    {
        /// <summary>
        /// 频道标题
        /// </summary>
        public string Title { get; set; }

        /// <summary>
        /// 频道文本
        /// </summary>
        public string Text { get; set; }

        /// <summary>
        /// 频道类型-RSS
        /// </summary>
        public string Type { get; set; }

        /// <summary>
        /// XML地址
        /// </summary>
        public string xmlUrl { get; set; }

        /// <summary>
        /// HTML地址
        /// </summary>
        public string htmlUrl { get; set; }

        private List<OutLine> _olChildren = new List<OutLine>();

        /// <summary>
        /// 子频道
        /// </summary>
        public List<OutLine> ChildrenOutline
        {
            get { return _olChildren; }
        }
    }

好，接下来对应的两类，分别获取频道列表和新闻列表。

    /// <summary>
    /// 新闻项管理类
    /// </summary>
    public class NewsManager
    {
        /// <summary>
        /// 根据输入的XML地址获取新闻列表。
        /// </summary>
        /// <param name="xmlUrl">新闻频道的XML地址</param>
        /// <returns>NewsItem的结果集合</returns>
        public List<NewsItem> GetNewsItemList(string xmlUrl)
        {
            List<NewsItem> _myNews = new List<NewsItem>();
            XElement myRoot = XElement.Load(xmlUrl);
            var theItems =
                from xe in myRoot.Element("channel").Elements("item")
                select xe;
            foreach (XElement e in theItems)
            {
                _myNews.Add(new NewsItem()
                {
                    Title = (string)e.Element("title"),
                    Link = (string)e.Element("link"),
                    Author = (string)e.Element("author"),
                    Category = (string)e.Element("category"),
                    PubDate = (DateTime)e.Element("pubDate"),
                    Comments = (string)e.Element("comments"),
                    Description = (string)e.Element("description")
                });
            }
            return _myNews;
        }
    }

    /// <summary>
    /// 自动获取频道列表类
    /// </summary>
    public class OutlineManager
    {
        /// <summary>
        /// 获取频道列表，包含子节点
        /// </summary>
        /// <param name="xmlUrl">根频道地址</param>
        /// <returns></returns>
        public List<OutLine> GetCannels(string xmlUrl)
        {
            List<OutLine> _list = new List<OutLine>();
            XElement root = XElement.Load(xmlUrl);
            var firstOutline = root.Element("body").Elements("outline");
            foreach (XElement xitem in firstOutline)
            {
                OutLine myRootOutline = new OutLine
                {
                    Title = (string)xitem.Attribute("title") ?? "",
                    Text = (string)xitem.Attribute("text") ?? "",
                    Type = (string)xitem.Attribute("type") ?? "",
                    xmlUrl = (string)xitem.Attribute("xmlUrl") ?? "",
                    htmlUrl = (string)xitem.Attribute("htmlUrl") ?? ""
                };
                AddChildElements(xitem, myRootOutline);
                _list.Add(myRootOutline);
            }
            return _list;
        }


        private void AddChildElements(XElement xNode, OutLine ol)
        {
            if (xNode == null) return;

            var xc = xNode.Elements("outline");
            // 递归，添加子节点
            foreach (XElement xe in xc)
            {
                OutLine outline = new OutLine()
                {
                    Title = xe.Attribute("title").Value,
                    Text = xe.Attribute("text").Value,
                    Type = xe.Attribute("type").Value,
                    xmlUrl = xe.Attribute("xmlUrl").Value,
                    htmlUrl = xe.Attribute("htmlUrl").Value
                };

                ol.ChildrenOutline.Add(outline);

                AddChildElements(xe, outline);
            }
        }
    }

OK，简单的类库写好了，程序集名称为SinaRssAPIs_CS，然后，我们建一个程序来测试一下。

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using SinaRssAPIs_CS;

namespace NewsApiTest
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            this.WindowState = FormWindowState.Maximized;
            this.Text = "新浪RSS类库示例程序";
            this.treeView1.AfterSelect += new TreeViewEventHandler(treeView1_AfterSelect);
            this.dataGridView1.AutoGenerateColumns = false; //不自动创建列
            //添加列
            DataGridViewTextBoxColumn colTitle = new DataGridViewTextBoxColumn();
            colTitle.HeaderText = "新闻标题";
            colTitle.DataPropertyName = "Title";
            this.dataGridView1.Columns.Add(colTitle);
            DataGridViewTextBoxColumn colDesc = new DataGridViewTextBoxColumn();
            colDesc.HeaderText = "描述";
            colDesc.DataPropertyName = "Description";
            colDesc.Width = 280;
            this.dataGridView1.Columns.Add(colDesc);
            DataGridViewTextBoxColumn colDate = new DataGridViewTextBoxColumn();
            colDate.DefaultCellStyle.Format = "yyyy-MM-dd";
            colDate.HeaderText = "发布日期";
            colDate.DataPropertyName = "PubDate";
            this.dataGridView1.Columns.Add(colDate);
            DataGridViewTextBoxColumn colAuthor = new DataGridViewTextBoxColumn();
            colAuthor.HeaderText = "发布者";
            colAuthor.DataPropertyName = "Author";
            this.dataGridView1.Columns.Add(colAuthor);
            DataGridViewTextBoxColumn colLink = new DataGridViewTextBoxColumn();
            colLink.DataPropertyName = "Link";
            colLink.Name = "link";
            colLink.Visible = false;
            this.dataGridView1.Columns.Add(colLink);

            this.dataGridView1.SelectionChanged += new EventHandler(dataGridView1_SelectionChanged);
        }

        void dataGridView1_SelectionChanged(object sender, EventArgs e)
        {
            if (this.dataGridView1.CurrentRow == null) return;
            string link = this.dataGridView1.CurrentRow.Cells["link"].Value.ToString();
            this.webBrowser1.Navigate(link);
        }

        void treeView1_AfterSelect(object sender, TreeViewEventArgs e)
        {
            if (e.Node.Tag == null) return;

            string xml = e.Node.Tag.ToString();
            List<NewsItem> items = null;
            NewsManager mg = new NewsManager();
            items = mg.GetNewsItemList(xml);

            this.dataGridView1.DataSource = items;

        }



        private void Form1_Load(object sender, EventArgs e)
        {
            OutlineManager omg = new OutlineManager();
            List<OutLine> cnList = omg.GetCannels(@"http://rss.sina.com.cn/sina_all_opml.xml");
            this.treeView1.BeginUpdate();
            this.treeView1.Nodes.Clear();
            //根节点
            foreach (OutLine  root in cnList)
            {
                TreeNode tnRoot = new TreeNode();
                tnRoot.Text = root.Title.Split('-')[0];
                AddNodes(root, tnRoot);
                this.treeView1.Nodes.Add(tnRoot);
            }
            this.treeView1.EndUpdate();
        }

        private void AddNodes(OutLine ol, TreeNode nd)
        {
            foreach (OutLine oits in ol.ChildrenOutline)
            {
                TreeNode tn = new TreeNode();
                tn.Text = oits.Title;
                tn.Tag = oits.xmlUrl;
                AddNodes(oits, tn);
                nd.Nodes.Add(tn);
            }
        }
    }
}

大致的运行效果如下：

现在，我说一下技术要点，不多，就一个，对，就是LinQ To XML。