Best approach for xpath on .NET 2.0 -- dotnet xml

David Thielen
10/5/2005 7:39:03 PM

Hello;

Sorry - I should not have used the word dataset. My xml will always come
from a Stream - usually a file.

--
thanks - dave

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v-kevy NO[at]SPAM online.microsoft.com
10/6/2005 12:00:00 AM

Hi Dave,

First of all, I would like to confirm my understanding of your issue. From
your description, I understand that you need to perform an XPath query on a
DataSet. If there is any misunderstanding, please feel free to let me know.

Here is a very good article dedicated on how to perform an XPath query on a
DataSet. Please check it and it will be helpful.

http://msdn2.microsoft.com/en-us/library/89tyw6dw

HTH.

Kevin Yu
=======
"This posting is provided "AS IS" with no warranties, and confers no
rights."

Martin Honnen
10/7/2005 12:00:00 AM

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No, XPathDocument is optimized for readonly XPath access. You only need
XmlDocument if you want to make changes to the XML.

--

Martin Honnen --- MVP XML

v-kevy NO[at]SPAM online.microsoft.com
10/7/2005 5:51:47 AM

Hi dave,

Doing XQuery in an XmlDocument is generally the same as mentioned in the
article I have provided. If you're getting the xml from a file, you can
first load it into an XmlDocument and then use XmlDocument.SelectNodes with
an xpath as argument to do the query. It is also the same as we did in .NET
1.1. Please also check the following link for more informatioin on
SelectNodes method.

http://msdn2.microsoft.com/en-us/library/hcebdtae

Kevin Yu
=======
"This posting is provided "AS IS" with no warranties, and confers no
rights."

David Thielen
10/7/2005 6:45:02 AM

Hello;

So XmlDocument is more efficient than XpathDocument? Ok, will go that route.

Out of curiosity why do they have XpathDocument then?

--
thanks - dave

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David Thielen
10/7/2005 7:18:07 AM

Hi;

That's what I thought. But Kevin Yu is, I am assuming, posting the official
MS suggestion. Any idea why he would prefer XmlDocument?

My use is xpath quieries only - so it is read-only.

--
thanks - dave

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David Thielen
10/9/2005 8:56:01 PM

Hi;

Can I assume that for the read-only case XpathDocument is faster?

--
thanks - dave

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Oleg Tkachenko [MVP]
10/10/2005 12:00:00 AM

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Sure. It's 30-50% faster than XmlDocument for XPath. Not to mention it
takes less memory.

--
Oleg Tkachenko [XML MVP, MCAD]
http://www.xmllab.net

v-kevy NO[at]SPAM online.microsoft.com
10/10/2005 12:00:00 AM

Hi dave,

I think there might be some misunderstanding here. Using XmlDocument or
XpathDocument depends on the scenario. As Martin said, in an readonly case,
we can use xpathdocument, however, if you need to do modifications, use
XmlDocument.

Kevin Yu
=======
"This posting is provided "AS IS" with no warranties, and confers no
rights."

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