XmlNodelist中的XmlNode

Question

有人知道哪里出错了吗？或者是将视频名称转换为字符串的更好方法？

string text = "<?xml version='1.0' encoding='UTF-8'?><feed xmlns='http://www.w3.org/2005/Atom' xmlns:media='http://search.yahoo.com/mrss/' xmlns:openSearch='http://a9.com/-/spec/opensearchrss/1.0/' xmlns:gd='http://schemas.google.com/g/2005' xmlns:yt='http://gdata.youtube.com/schemas/2007'><entry><title>VIDEO NAME</title></entry></feed>";
string xpath = "feed/entry";
XmlDocument xml = new XmlDocument();
xml.LoadXml(text);
XmlNodeList nodes = xml.SelectNodes(xpath);
foreach (XmlNode node in nodes)
{
    string title = node["title"].InnerText;
    MessageBox.Show(title);
}

XML

<?xml version='1.0' encoding='UTF-8'?>
    <feed xmlns='http://www.w3.org/2005/Atom' xmlns:media='http://search.yahoo.com/mrss/' xmlns:openSearch='http://a9.com/-/spec/opensearchrss/1.0/' xmlns:gd='http://schemas.google.com/g/2005' xmlns:yt='http://gdata.youtube.com/schemas/2007'>
      <entry>
        <title>VIDEO NAME</title>
      </entry>
    </feed>

Answer 1

Xml xmlns='http://www.w3.org/2005/Atom'中的这个声明将文档中所有没有名称空间前缀的元素放在默认名称空间http://www.w3.org/2005/Atom/中。因此，您需要在XPath查询中使用名称空间：

        string text = "<?xml version='1.0' encoding='UTF-8'?><feed xmlns='http://www.w3.org/2005/Atom' xmlns:media='http://search.yahoo.com/mrss/' xmlns:openSearch='http://a9.com/-/spec/opensearchrss/1.0/' xmlns:gd='http://schemas.google.com/g/2005' xmlns:yt='http://gdata.youtube.com/schemas/2007'><entry><title>VIDEO NAME</title></entry></feed>";

        XmlDocument xml = new XmlDocument();
        xml.LoadXml(text);
        XmlNamespaceManager nsmgr = new System.Xml.XmlNamespaceManager(xml.NameTable);
        nsmgr.AddNamespace("atom", "http://www.w3.org/2005/Atom");
        string xpath = "atom:feed/atom:entry/atom:title";
        XmlNodeList nodes = xml.SelectNodes(xpath, nsmgr);

        foreach (XmlNode node in nodes)
        {
            Console.WriteLine(node.InnerText);
        }

Answer 2

您可以使用LINQ to XML代替XmlDocument和XPath：

string text = "<?xml version='1.0' encoding='UTF-8'?><feed xmlns='http://www.w3.org/2005/Atom' xmlns:media='http://search.yahoo.com/mrss/' xmlns:openSearch='http://a9.com/-/spec/opensearchrss/1.0/' xmlns:gd='http://schemas.google.com/g/2005' xmlns:yt='http://gdata.youtube.com/schemas/2007'><entry><title>VIDEO NAME</title></entry></feed>";
var doc = XDocument.Parse(text);
var atom = XNamespace.Get("http://www.w3.org/2005/Atom");

var titles = doc.Descendants(atom + "entry")
                .Select(e => (string)e.Element(atom + "title"))
                .ToList();

foreach (string title in titles)
    Console.WriteLine(title);

Answer 3

这是可行的，但我生成的代码感觉就像是一个肮脏的黑客

        string text = "<?xml version='1.0' encoding='UTF-8'?><feed xmlns='http://www.w3.org/2005/Atom' xmlns:media='http://search.yahoo.com/mrss/' xmlns:openSearch='http://a9.com/-/spec/opensearchrss/1.0/' xmlns:gd='http://schemas.google.com/g/2005' xmlns:yt='http://gdata.youtube.com/schemas/2007'><entry><title>VIDEO NAME</title></entry></feed>";
        XmlDocument xml = new XmlDocument();
        xml.LoadXml(text);
        XmlNode parentNode = xml.GetElementsByTagName("feed").Item(0);
        foreach (XmlNode n in parentNode.ChildNodes)
        {
            string title = n["title"].InnerText;
            Console.WriteLine(title);
        }

        Console.ReadLine();