XML namespaces and prefix

[Jeremy Chapman]

I am trying to use xpath queries on an xmldocument passed to my web service.
The document nodes have namespace prefixes. How can I programatically
create an xpath query and run it assuming that the namespace and prefix
could potentially change?

Here is an example of my xml (from an infopath form in this case, but could
be from any application)

<?xml version="1.0" encoding="UTF-8"?>
<?mso-infoPathSolution solutionVersion="1.0.0.52" productVersion="11.0.6357"
PIVersion="1.0.0.0"
href="http://testmachine/infopathforms/DocumentLibraryTest.xsn"
name="urn:schemas-microsoft-com:office:infopath:DocumentLibraryTest:-myXSD-2005-07-28T21-22-28"
?><?mso-application progid="InfoPath.Document"?>
<my:Form xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:my="http://schemas.microsoft.com/office/infopath/2003/myXSD/2005-07-28T21:22:28"
xmlns:xd="http://schemas.microsoft.com/office/infopath/2003"
xml:lang="en-us">
<my:Header>
<my:PHN>1234</my:PHN>
</my:Header>
<my:Footer>
<my:DateCompleted>2005-08-04</my:DateCompleted>
<my:CompletedBy>123</my:CompletedBy>
</my:Footer>
<my:Description>
<my:Text></my:Text>
</my:Description>
<my:Extra>
<my:Active>false</my:Active>
<my:ExtraText></my:ExtraText>
</my:Extra>
</my:Form>

[Marvin Smit]

Hi,

Ehh.. if you say "assuming that the namespace and prefix could
potentially change" it is a strange construct. If a namespace would
'suddenly change', all clients would have problems. This is usualy a
'versioning' step that happened. My advise is ALWAYS change the
namespace uri, if the schema constructs change. But, maintain the
precious versions of the schema. Do not overwrite the old one.
For this example you should do something like:
(From the top of my head, forgive me any typo's)

XmlNamespaceManager xNS = new XmlNamespaceManager( new NameTable () );
xNS.AddNamespace( "prefix", "namespaceUri" );

XmlDocument xDoc = new XmlDocument();
xDoc.Load( @"C:\temp\somexml.xml" );

XmlNodeList xNL = xDoc.DocumentElement.SelectNodes (
"prefix:MainRoot/prefix:SomeChild" );
Hope this helps,

Marvin Smit.
On Fri, 29 Jul 2005 11:06:57 -0700, "Jeremy Chapman" <[e-mail]>
wrote:

I am trying to use xpath queries on an xmldocument passed to my web service.
The document nodes have namespace prefixes. How can I programatically
create an xpath query and run it assuming that the namespace and prefix
could potentially change?

Here is an example of my xml (from an infopath form in this case, but could
be from any application)

<?xml version="1.0" encoding="UTF-8"?>
<?mso-infoPathSolution solutionVersion="1.0.0.52" productVersion="11.0.6357"
PIVersion="1.0.0.0"
href="http://testmachine/infopathforms/DocumentLibraryTest.xsn"
name="urn:schemas-microsoft-com:office:infopath:DocumentLibraryTest:-myXSD-2005-07-28T21-22-28"
?><?mso-application progid="InfoPath.Document"?>
<my:Form xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:my="http://schemas.microsoft.com/office/infopath/2003/myXSD/2005-07-28T21:22:28"
xmlns:xd="http://schemas.microsoft.com/office/infopath/2003"
xml:lang="en-us">
<my:Header>
<my:PHN>1234</my:PHN>
</my:Header>
<my:Footer>
<my:DateCompleted>2005-08-04</my:DateCompleted>
<my:CompletedBy>123</my:CompletedBy>
</my:Footer>
<my:Description>
<my:Text></my:Text>
</my:Description>
<my:Extra>
<my:Active>false</my:Active>
<my:ExtraText></my:ExtraText>
</my:Extra>
</my:Form>