您必须先
dc使用XmlNamespaceManager声明名称空间前缀，然后才能在XPath表达式中使用它：
Xmldocument rssDoc = new Xmldocument();rssDoc.Load(rssStream);XmlNamespaceManager nsmgr = new XmlNamespaceManager(rssDoc.Nametable);nsmgr.AddNamespace("dc", "http://purl.org/dc/elements/1.1/");XmlNodeList rssItems = rssDoc.SelectNodes("rss/channel/item");for (int i = 0; i < 5; i++) { XmlNode rssDetail = rssItems[i].SelectSingleNode("dc:creator", nsmgr); if (rssDetail != null) { user = rssDetail.InnerText; } else { user = ""; }}
