XPath查询选择节点时，属性不存在？ [英] Xpath query to select node when attribute does not exist?

问题描述

我想以选择一个特定的属性不存在的节点。我已经试过not（）函数，但它不工作。是否有此问题的方法？

I want to select nodes for which a specific attribute does not exist. I've tried the Not() function, but it doesn't work. Is there a way for this?

例如：
以下XPath查询：

Example: The following Xpath query:

group/msg[not(@owner)]

如果检索的第一个节点，但不是第二之一。但是，这两个SketchPath（工具测试Xpath查询）和我的C＃code认为2个节点都ok。

Should retrieve the first node but not the 2nd one. However, both SketchPath (tool to test Xpath queries) and my C# code consider that the 2 nodes are ok.

<group>
    <msg id="EVENTDATA_CCFLOADED_XMLCONTEXT"  numericId="14026"  translate="False"  topicId="302"  status="translated" >
        <text>Context</text>
        <comment></comment>
    </msg>
    <msg id="EVENTDATA_CCFLOADED_XMLCONTEXT_HELP"  numericId="14027"  translate="False"  topicId="302"  status="translated"  owner="EVENTDATA_CCFLOADED_XMLCONTEXT" >
        <text>Provides the new data displayed in the Object.</text>
        <comment></comment>
    </msg>
</group>

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事实上，not（）函数正常工作，它只是我有其他条件和括号设定不正确。的 errare humanum EST 的

In fact the Not() function works correctly, it's just that I had other conditions and parentheses weren't set correctly. errare humanum est.

推荐答案

在一些老的，不太标准的XPath引擎，我不得不使用字符串长度（@attr）= 0 出于同样的原因。

In some old and not very standard XPath engine I had to use string-length(@attr)=0 for the same reason.

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