-- 作者：dakzhang
-- 发布时间：5/25/2006 12:26:00 PM
-- NET中如何判断XPATH语句执行结果为空！！！
废了九牛二虎之力，终于找到了
使用Object.ReferenceEquals 方法，具体代码如下： XmlDocument doc = new XmlDocument();
doc.Load(Server.MapPath("books.xml"));
XmlElement root; root = (XmlElement)doc.SelectSingleNode("/booksort/book[1]/prices");
bool Is_Null=object.ReferenceEquals(root,null);
if(Is_Null == true)
{
Response.Write("Xpath表达式执行结果为空");
}
books.xmll如下：
<?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>
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