XPathNavigator类包含移动和选择XML所需元素的所有方法。 1.创建： a.如果是从XPathDocument中创建，则是只读的，只能浏览数据； b.如果是从XmlDocument中创建，则可以编辑文档； 2.查询：使用Select()方法通过XPath语句查询； 3.迭代：使用XPathNodeIterator类，MoveNext()方法移动下一个节点；Current属性表示当前节点； 4.求值：使用Evaluate()方法计算表达式的值； 5.插入节点：先检查CanEdit属性是否为true，再使用InsertAfter()方法插入新节点。 实例：查询和编辑books.xml
01. using System; 02. using System.Collections.Generic; 03. using System.Text; 04. using System.Xml.XPath; 05. using System.Xml; 06. 07. namespace Magci.Test.XML.TestXPath 08. { 09. class Program 10. { 11. private static XPathDocument doc; 12. private static XPathNavigator nav; 13. 14. static void Main( string [] args) 15. { 16. doc = new XPathDocument(@ "../../books.xml" ); 17. nav = ((IXPathNavigable)doc).CreateNavigator(); 18. SearchByGenre( "nove" ); 19. TotalPrice(); 20. Insert(); 21. Console.ReadLine(); 22. } 23. 24. public static void SearchByGenre( string search) 25. { 26. //查询bookstore的子元素book中genre属性值为novel的所有节点 27. XPathNodeIterator iter = nav.Select( "/bookstore/book[@genre='" + search + "l']" ); 28. 29. Console.WriteLine( "/nSearchByGenre:/n" ); 30. while (iter.MoveNext()) 31. { 32. //迭代所有子代节点 33. XPathNodeIterator newIter = iter.Current.SelectDescendants(XPathNodeType.Element, false ); 34. while (newIter.MoveNext()) 35. { 36. Console.WriteLine(newIter.Current.Name + " : " + newIter.Current.Value); 37. } 38. } 39. } 40. 41. public static void TotalPrice() 42. { 43. XPathNodeIterator iter = nav.Select( "/bookstore/book" ); 44. Console.WriteLine( "/nTotalPrice:/n" ); 45. while (iter.MoveNext()) 46. { 47. XPathNodeIterator newIter = iter.Current.SelectDescendants(XPathNodeType.Element, false ); 48. while (newIter.MoveNext()) 49. { 50. if (newIter.Current.Name == "price" ) 51. { 52. Console.WriteLine(newIter.Current.Name + " : " + newIter.Current.Value); 53. } 54. } 55. } 56. //统计图书总价 57. Console.WriteLine( "Total price = {0}" , nav.Evaluate( "sum(bookstore/book/price)" )); 58. } 59. 60. //插入节点 61. public static void Insert() 62. { 63. XmlDocument doc = new XmlDocument(); 64. doc.Load(@ "../../books.xml" ); 65. XPathNavigator nav2 = doc.CreateNavigator(); 66. //判断是否可编辑 67. if (nav2.CanEdit) 68. { 69. XPathNodeIterator iter = nav2.Select( "bookstore/book/price" ); 70. while (iter.MoveNext()) 71. { 72. //在当前节点之后插入新节点 73. iter.Current.InsertAfter( "<disc>5</disc>" ); 74. } 75. } 76. doc.Save(@ "../../newBooks.xml" ); 77. Console.WriteLine( "/nnewBooks.xml saved successful./n" ); 78. } 79. } 80. } book.xml: 01. <? xml version = "1.0" encoding = "utf-8" ?> 02. < bookstore > 03. < book genre = "autobiography" publicationdate = "1991" ISBN = "1-861003-11-0" > 04. < title >The Autobiography of Benjamin Franklin</ title > 05. < author > 06. < first-name >Benjamin</ first-name > 07. < last-name >Franklin</ last-name > 08. </ author > 09. < price >8.99</ price > 10. </ book > 11. < book genre = "novel" publicationdate = "1967" ISBN = "0-201-63361-2" > 12. < title >The Confidence Man</ title > 13. < author > 14. < first-name >Herman</ first-name > 15. < last-name >Melville</ last-name > 16. </ author > 17. < price >11.99</ price > 18. </ book > 19. < book genre = "philosophy" publicationdate = "1991" ISBN = "1-861001-57-6" > 20. < title >The Gorgias</ title > 21. < author > 22. < name >Plato</ name > 23. </ author > 24. < price >9.99</ price > 25. </ book > 26. </ bookstore > newBooks.xml:编辑后的文档 01. <? xml version = "1.0" encoding = "utf-8" ?> 02. < bookstore > 03. < book genre = "autobiography" publicationdate = "1991" ISBN = "1-861003-11-0" > 04. < title >The Autobiography of Benjamin Franklin</ title > 05. < author > 06. < first-name >Benjamin</ first-name > 07. < last-name >Franklin</ last-name > 08. </ author > 09. < price >8.99</ price > 10. < disc >5</ disc > 11. </ book > 12. < book genre = "novel" publicationdate = "1967" ISBN = "0-201-63361-2" > 13. < title >The Confidence Man</ title > 14. < author > 15. < first-name >Herman</ first-name > 16. < last-name >Melville</ last-name > 17. </ author > 18. < price >11.99</ price > 19. < disc >5</ disc > 20. </ book > 21. < book genre = "philosophy" publicationdate = "1991" ISBN = "1-861001-57-6" > 22. < title >The Gorgias</ title > 23. < author > 24. < name >Plato</ name > 25. </ author > 26. < price >9.99</ price > 27. < disc >5</ disc > 28. </ book > 29. </ bookstore >
