XmlDocument.SelectNodes 不起作用

今天采用Xpath读取Xml节点，怎么都读不出。

问题分析：

错误代码如下：

      XmlDocument xmlD = new XmlDocument();xmlD.PreserveWhitespace = true;xmlD.LoadXml(xStr);xmlD.SelectNodes(@"job-scheduling-data/schedule/job");

经排查 dotnet 文档，发现代码编写没有问题。文档描述如下：

文档示例如下：
示例代码：

using System;
using System.IO;
using System.Xml;public class Sample
{public static void Main(){XmlDocument doc = new XmlDocument();doc.Load("booksort.xml");//Create an XmlNamespaceManager for resolving namespaces.XmlNamespaceManager nsmgr = new XmlNamespaceManager(doc.NameTable);nsmgr.AddNamespace("bk", "urn:samples");//Select and display the value of all the ISBN attributes.XmlNodeList nodeList;XmlElement root = doc.DocumentElement;nodeList = root.SelectNodes("/bookstore/book/@bk:ISBN", nsmgr);foreach (XmlNode isbn in nodeList){Console.WriteLine(isbn.Value);}}
}

示例XML：

<?xml version="1.0"?>
<!-- A fragment of a book store inventory database -->
<bookstore xmlns:bk="urn:samples"><book genre="novel" publicationdate="1997" bk:ISBN="1-861001-57-8"><title>Pride And Prejudice</title><author><first-name>Jane</first-name><last-name>Austen</last-name></author><price>24.95</price></book><book genre="novel" publicationdate="1992" bk:ISBN="1-861002-30-1"><title>The Handmaid's Tale</title><author><first-name>Margaret</first-name><last-name>Atwood</last-name></author><price>29.95</price></book><book genre="novel" publicationdate="1991" bk:ISBN="1-861001-57-6"><title>Emma</title><author><first-name>Jane</first-name><last-name>Austen</last-name></author><price>19.95</price></book><book genre="novel" publicationdate="1982" bk:ISBN="1-861001-45-3"><title>Sense and Sensibility</title><author><first-name>Jane</first-name><last-name>Austen</last-name></author><price>19.95</price></book>
</bookstore>

自己程序采用Xml：

结论：问题原因：最后用文档示例与自己代码比较发现上命名空间导致**

修改后正确代码

     string xStr = File.ReadAllText(path.Trim());xStr = xStr.Replace("<?xml version=\"1.0\" encoding=\"utf-8\"?>", "");xStr = xStr.Replace("xmlns=\"http://quartznet.sourceforge.net/JobSchedulingData\"", "");xStr = xStr.Replace("xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\"", "");XmlDocument xmlD = new XmlDocument();xmlD.PreserveWhitespace = true;xmlD.LoadXml(xStr);XmlNodeList jobNodeList = xmlD.SelectNodes(@"job-scheduling-data/schedule/job");