如何:查找父元素的属性 (XPath-LINQ to XML)
更新:November 2007
本主题演示如何定位到父元素并查找其属性。
XPath 表达式为:
../@id
示例
此示例首先查找 Author 元素。 然后,查找父元素的 id 属性。
本示例使用下面的 XML 文档:示例 XML 文件:图书 (LINQ to XML)。
XDocument books = XDocument.Load("Books.xml");
XElement author =
books
.Root
.Element("Book")
.Element("Author");
// LINQ to XML query
XAttribute att1 =
author
.Parent
.Attribute("id");
// XPath expression
XAttribute att2 = ((IEnumerable)author.XPathEvaluate("../@id")).Cast<XAttribute>().First();
if (att1 == att2)
Console.WriteLine("Results are identical");
else
Console.WriteLine("Results differ");
Console.WriteLine(att1);
Dim books As XDocument = XDocument.Load("Books.xml")
Dim author As XElement = books.Root.<Book>.<Author>.FirstOrDefault()
' LINQ to XML query
Dim att1 As XAttribute = author.Parent.Attribute("id")
' XPath expression
Dim att2 As XAttribute = DirectCast(author.XPathEvaluate("../@id"), _
IEnumerable).Cast(Of XAttribute)().First()
If att1 Is att2 Then
Console.WriteLine("Results are identical")
Else
Console.WriteLine("Results differ")
End If
Console.WriteLine(att1)
本示例生成以下输出:
Results are identical
id="bk101"