RE: XmlDocument.SelectSingleNode XPathException

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Thanks for your reply Dave,

As you said:
===========
The "xmlns:sns="http://www.test.org/sub";>" in the xml itself provides the
necessary information to turn:
//sns:subItem[@sid="11"]
into:
//http://www.test.org/sub:subItem[@sid="11";]
===========

yes, the XML Node or fragment did include the namespace declaraion.
However, this doesn't means that our XPATH can only use "sns" to idenity
the "http://www.test.org/sub"; namespace. The "sns" is only an alias. So
the following two xml fragment should be identical (validate through schema)

#fragment A
<root xmlns:sns="http://www.test.org/sub";>
<sns:item>
.......
</sns:item>
</root>

#fragment B
<root xmlns:aaa="http://www.test.org/sub";>
<aaa:item>
.......
</aaa:item>
</root>

However, if we only use the

"//sns:item" xpath and haven't specify an prefix/ URI mapping, it
will only work( using the JAVA API you mentioned) in

fragment A , but not in fragment B( though framgment A is exactly the same
xml document as fragment B).

And when using .net's Xpath selection, since we specify the
XmlNamespaceManager which provide the prefix(in our xpath) ----
namespaceURI mapping , we can perform the xpath selection no matter the
namespace prefix is changed to anyone in the source xml document. Also,
the prefix in our XPATH can vary , such as :

//bbb:item using AddNamespace("bbb", "http://test.org/sub";)

//ccc:item using AddNamespace("ccc", "http://test.org/sub";)

Anyway, I think the prefix( in xpath ) is not simply an alias( it should
always has a namespaceURI mapped to it) , otherwise, the prefix will be
meaningless alone.

Just some of my understanding. Thanks,

Steven Cheng
Microsoft Online Support

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