HtmlAgilityPack使用(一)【获取文档链接】

GetDocLinks.cs代码:

using System;
using System.Collections;

namespace HtmlAgilityPack.Samples
{
    //获取文档链接
    class GetDocLinks
    {
        [STAThread]
        static void Main(string[] args)
        {
            HtmlWeb hw = new HtmlWeb();
            string url = @"http://www.microsoft.com";
            HtmlDocument doc = hw.Load(url);
            doc.Save("mshome.htm");

            DocumentWithLinks nwl = new DocumentWithLinks(doc);
            Console.WriteLine("链接 urls:");
            for(int i=0;i<nwl.Links.Count;i++)
            {
                Console.WriteLine(nwl.Links[i]);
            }

            Console.WriteLine("引用 urls:");
            for(int i=0;i<nwl.References.Count;i++)
            {
                Console.WriteLine(nwl.References[i]);
            }
            Console.ReadKey();
        }
    }

    /// <summary>
    /// Represents a document that needs linked files to be rendered, such as images or css files, and points to other HTML documents.
    /// 表示需要呈现链接文件的文档，如图像或CSS文件，并指向其他HTML文档。
    /// </summary>
    public class DocumentWithLinks
    {
        private ArrayList _links;
        private ArrayList _references;
        private HtmlDocument _doc;

        /// <summary>
        /// 创建一个DocumentWithLinkedFiles的实例。
        /// </summary>
        /// <param name="doc">输入HTML文件。不可能为null。</param>
        public DocumentWithLinks(HtmlDocument doc)
        {
            if (doc == null)
            {
                throw new ArgumentNullException("doc");
            }
            _doc = doc;
            GetLinks();
            GetReferences();
        }

        private void GetLinks()
        {
            _links = new ArrayList();
            HtmlNodeCollection atts = _doc.DocumentNode.SelectNodes("//*[@background or @lowsrc or @src or @href]");
            if (atts == null)
                return;

            foreach(HtmlNode n in atts)
            {
                ParseLink(n, "background");
                ParseLink(n, "href");
                ParseLink(n, "src");
                ParseLink(n, "lowsrc");
            }
        }

        private void GetReferences()
        {
            _references = new ArrayList();
            HtmlNodeCollection hrefs = _doc.DocumentNode.SelectNodes("//a[@href]");
            if (hrefs == null)
                return;

            foreach(HtmlNode href in hrefs)
            {
                _references.Add(href.Attributes["href"].Value);
            }
        }


        private void ParseLink(HtmlNode node, string name)
        {
            HtmlAttribute att = node.Attributes[name];
            if (att == null)
                return;

            //如果name = href，我们只对<link>标签感兴趣
            if ((name == "href") && (node.Name != "link"))
                return;

            _links.Add(att.Value);
        }

        /// <summary>
        /// 获取在HTML文档中声明的链接列表
        /// </summary>
        public ArrayList Links
        {
            get
            {
                return _links;
            }
        }

        /// <summary>
        /// 获取其他HTML文档的引用链接列表，因为它们是在HTML文档中声明的。
        /// </summary>
        public ArrayList References
        {
            get
            {
                return _references;
            }
        }
    }
}

运行结果如图:

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