Search code examples
c#xmlreader

Parsing through XML elements in XmlReader


I'm building an application that needs to run through an XML feed but I'm having a little trouble with getting certain elements.

I'm using the Twitter feed and want to run through all the <item> elements. I can connect fine and get the content from the feed but I can't figure out how to select only the item elements when I'm loopuing through reader.Read();.

Thanks for your help!


Solution

  • The easiest way to do that is to use XPath. Example to follow.

     string xml = @"<?xml version=""1.0"" encoding=""UTF-8""?>
    <rss version=""2.0"">
        <channel>
        <title>Twitter public timeline</title>
        <link>http://twitter.com/public_timeline</link>
        <description>Twitter updates from everyone!</description>
        <language>en-us</language>
        <ttl>40</ttl>
    
        <item>
          <title>yasu_kobayashi: rTwT: @junm : yayaya</title>
          <description>yasu_kobayashi: rTwT: @junm : yayaya</description>
          <pubDate>Tue, 28 Oct 2008 12:04:48 +0000</pubDate>
          <guid>http://twitter.com/yasu_kobayashi/statuses/978829930</guid>
          <link>http://twitter.com/yasu_kobayashi/statuses/978829930</link>
    
        </item><item>
          <title>FreeGroup: WikiFortio - foobar http://tinyurl.com/5gvttf</title>
          <description>FreeGroup: WikiFortio - foobar
          http://tinyurl.com/5gvttf</description>
          <pubDate>Tue, 28 Oct 2008 12:04:47 +0000</pubDate>
          <guid>http://twitter.com/FreeGroup/statuses/978829929</guid>
          <link>http://twitter.com/FreeGroup/statuses/978829929</link>
    
        </item></channel></rss>
            ";
                XPathDocument doc = new XPathDocument(new StringReader(xml));
                XPathNavigator nav = doc.CreateNavigator();
    
                // Compile a standard XPath expression
    
                XPathExpression expr;
                expr = nav.Compile("/rss/channel/item");
                XPathNodeIterator iterator = nav.Select(expr);
    
                // Iterate on the node set
    
                try
                {
                    while (iterator.MoveNext())
                    {
                        XPathNavigator nav2 = iterator.Current.Clone();
                        nav2.MoveToChild("title","");
                        Console.WriteLine(nav2.Value);
                        nav2.MoveToParent();
                        nav2.MoveToChild("pubDate","");
                        Console.WriteLine(nav2.Value);
    
                    }
                }
                catch (Exception ex)
                {
                    Console.WriteLine(ex.Message);
                }
                Console.ReadKey();
    

    And this is jan's approach working

            XmlDocument doc2 = new XmlDocument();
            doc2.LoadXml(xml);
            XmlNode root = doc2.DocumentElement;
    
            foreach (XmlNode item in root.SelectNodes(@"/rss/channel/item"))
            {
                Console.WriteLine(item.SelectSingleNode("title").FirstChild.Value);
                Console.WriteLine(item.SelectSingleNode("pubDate").FirstChild.Value);
            }