xpath查询返回空值 [英] xpath Query return null value

问题描述

<Header>
      <reference>
        <identifier>BatchProcessed</identifier>
        <datetime>2011-08-15T05:12:00+10:00</datetime>
      </reference>
    </Header>
    <Header>
      <reference>
        <identifier>Running</identifier>
        <datetime>2011-08-15T05:12:00+10:00</datetime>
      </reference>
    </Header>

我的xpath查询是

my xpath query is

XmlNode node3 = xdoc.SelectSingleNode("//identifier/text()");

该查询假定获取第一个标识符值"BatchProcessed".

但是当我测试时返回null，但是当我在xml工具(在线)中使用路径时，它会重新运行值.

我不知道这里缺少什么，有人启发了我.

the query suppose to get the first identifier value " BatchProcessed".

but it returns null when i test but when i use the path in xml tool (online) it retruns value.

i don''t know what am missing here,some one enlighten me

推荐答案

您不应使用text().只需获取节点，然后在代码中获取节点的值即可. XPath的含义可能会有所不同.使用//也很浪费，如果XML增长了，您会发现它比在要搜索的路径中显示得更慢.

You should not use text(). Just get the node, and then get the value of the node in code. XPath implimentations can vary. Using // is also wasteful, if your XML grows, you will find that it''s slower than being more explicit in the path you want to search.

因为您想要第一个标识符要显示的值，您可以通过以下方式实现:

Since you want the first identifier''s value to be shown, you can do it in this way:

string value = xdoc.SelectSingleNode("//identifier[position()=1]").InnerText; //Returns BatchProcessed

希望对您有所帮助.

Hope this helps.

将其显示为

xdoc.SelectSingleNode("//* [local-name()=''ServiceId'']"));

figured it out

xdoc.SelectSingleNode("//*[local-name()=''ServiceId'']");

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