selecting specific elements with xpath

[Lawrence Oluyede]

I've some problems with filtering out a specific element by the following
xml snippet (is part of a bigger xml document):

<entry>
<link href="http://www.blogger.com/atom/5281182/108809850419059234"
rel="service.edit" title="test" type="application/x.atom+xml"/>
<author>
<name>Lawrence</name>
</author>
<issued>2004-06-24T19:34:04+02:00</issued>
<modified>2004-06-24T17:35:04Z</modified>
<created>2004-06-24T17:35:04Z</created>
<link href="http://loluyede.blogspot.com/2004/06/test_24.html"
rel="alternate" title="test" type="text/html"/>
<id>tag:blogger.com,1999:blog-5281182.post-108809850419059234</id>
<title mode="escaped" type="text/html">test</title>
<content type="application/xhtml+xml"
xml:base="http://loluyede.blogspot.com" xml:lang="en-US"
xml:space="preserve">
<div xmlns="http://www.w3.org/1999/xhtml">this test is a post</div>
</content>
</entry>

The code I use is (assume that navigator is positioned on the <entry>
element):

XPathNavigator nav = navigator.Clone();
XPathNodeIterator iter = nav.SelectDescendants(XPathNodeType.Element,
true);

iter = nav.Select("//link[@type=\"text/html\" and @rel=\"alternate\"]");

and it returns me 0 nodes, instead if i copy and paste the above snippet in
a single document (so <entry> becomes the root) and open it with
XPathDocument the above code works, why?

--
Lawrence
"ain't nothin' but fun."

[Oleg Tkachenko [MVP]]

Lawrence Oluyede wrote:

XPathNodeIterator iter = nav.SelectDescendants(XPathNodeType.Element,
true);

iter = nav.Select("//link[@type=\"text/html\" and @rel=\"alternate\"]");

That's sort of weird. You select descendants and then discarding the
variable, making another selection. What's the point of the
SelectDescendants() call?

--
Oleg Tkachenko [XML MVP]
http://blog.tkachenko.com

[Oleg Tkachenko [MVP]]

Lawrence Oluyede wrote:

XPathNodeIterator iter = nav.SelectDescendants(XPathNodeType.Element,
true);

iter = nav.Select("//link[@type=\"text/html\" and @rel=\"alternate\"]");

That's sort of weird. You select descendants and then discarding the
variable, making another selection. What's the point of the
SelectDescendants() call?

--
Oleg Tkachenko [XML MVP]
http://blog.tkachenko.com

[Lawrence Oluyede]

In data Sun, 27 Jun 2004 14:29:35 +0200, Oleg Tkachenko [MVP] ha scritto:

That's sort of weird. You select descendants and then discarding the
variable, making another selection. What's the point of the
SelectDescendants() call?

Yeah you're right but removing that call doesn't solve the problem :(

--
Lawrence
"ain't nothin' but fun."

[Lawrence Oluyede]

In data Sun, 27 Jun 2004 14:29:35 +0200, Oleg Tkachenko [MVP] ha scritto:

That's sort of weird. You select descendants and then discarding the
variable, making another selection. What's the point of the
SelectDescendants() call?

Yeah you're right but removing that call doesn't solve the problem :(

--
Lawrence
"ain't nothin' but fun."

[Oleg Tkachenko [MVP]]

Lawrence Oluyede wrote:

iter = nav.Select("//link[@type=\"text/html\" and @rel=\"alternate\"]");

and it returns me 0 nodes, instead if i copy and paste the above snippet in
a single document (so <entry> becomes the root) and open it with
XPathDocument the above code works, why?

Chances are you've got namespaces involved. Show us entry ancestors.

--
Oleg Tkachenko [XML MVP]
http://blog.tkachenko.com

[Oleg Tkachenko [MVP]]

Lawrence Oluyede wrote:

iter = nav.Select("//link[@type=\"text/html\" and @rel=\"alternate\"]");

and it returns me 0 nodes, instead if i copy and paste the above snippet in
a single document (so <entry> becomes the root) and open it with
XPathDocument the above code works, why?

Chances are you've got namespaces involved. Show us entry ancestors.

--
Oleg Tkachenko [XML MVP]
http://blog.tkachenko.com

[Lawrence Oluyede]

In data Sun, 27 Jun 2004 15:08:52 +0200, Oleg Tkachenko [MVP] ha scritto:

Chances are you've got namespaces involved. Show us entry ancestors.

The file is http://loluyede.blogspot.com/atom.xml

Thanks!

--
Lawrence
" It's probably for the best. What use does Microsoft have for an employee
who knows the W3C standards?"
-- an anonymous about tantek departure from microsoft

[Lawrence Oluyede]

In data Sun, 27 Jun 2004 15:08:52 +0200, Oleg Tkachenko [MVP] ha scritto:

Chances are you've got namespaces involved. Show us entry ancestors.

The file is http://loluyede.blogspot.com/atom.xml

Thanks!

--
Lawrence
" It's probably for the best. What use does Microsoft have for an employee
who knows the W3C standards?"
-- an anonymous about tantek departure from microsoft

[Oleg Tkachenko [MVP]]

Lawrence Oluyede wrote:

Chances are you've got namespaces involved. Show us entry ancestors.

The file is http://loluyede.blogspot.com/atom.xml

Yeah, I was right. Look at this:

<feed version="0.3" xmlns="http://purl.org/atom/ns#">

That xmlns="http://purl.org/atom/ns#" is default namespace declaration.
That means feed element and all its descendants elements are in
"http://purl.org/atom/ns#" namespace.

Read about default namespace and XPath (there was good article at
Extreme XML column a couple of years ago) and take a look at
XPathNavigator.Select(XPathExpression) method documentation for a sample
of selecting nodes with default namespace involved.

--
Oleg Tkachenko [XML MVP]
http://blog.tkachenko.com

[Oleg Tkachenko [MVP]]

Lawrence Oluyede wrote:

Chances are you've got namespaces involved. Show us entry ancestors.

The file is http://loluyede.blogspot.com/atom.xml

Yeah, I was right. Look at this:

<feed version="0.3" xmlns="http://purl.org/atom/ns#">

That xmlns="http://purl.org/atom/ns#" is default namespace declaration.
That means feed element and all its descendants elements are in
"http://purl.org/atom/ns#" namespace.

Read about default namespace and XPath (there was good article at
Extreme XML column a couple of years ago) and take a look at
XPathNavigator.Select(XPathExpression) method documentation for a sample
of selecting nodes with default namespace involved.

--
Oleg Tkachenko [XML MVP]
http://blog.tkachenko.com

[Lawrence Oluyede]

In data Sun, 27 Jun 2004 18:19:37 +0200, Oleg Tkachenko [MVP] ha scritto:

Yeah, I was right. Look at this:

<feed version="0.3" xmlns="http://purl.org/atom/ns#">
Yeah I did know because I've added namespace capability for the parsing
object model, maybe that part doesn't recognize the namespace declaration
That xmlns="http://purl.org/atom/ns#" is default namespace declaration.
That means feed element and all its descendants elements are in
"http://purl.org/atom/ns#" namespace.
Right
Read about default namespace and XPath (there was good article at
Extreme XML column a couple of years ago)
I know, I've read it sometimes ago
and take a look at
XPathNavigator.Select(XPathExpression) method documentation for a sample
of selecting nodes with default namespace involved.

I try to "wire in" the namespace declaration, thanks!

--
Lawrence
" It's probably for the best. What use does Microsoft have for an employee
who knows the W3C standards?"
-- an anonymous about tantek departure from microsoft

[Lawrence Oluyede]

In data Sun, 27 Jun 2004 18:19:37 +0200, Oleg Tkachenko [MVP] ha scritto:

Yeah, I was right. Look at this:

<feed version="0.3" xmlns="http://purl.org/atom/ns#">
Yeah I did know because I've added namespace capability for the parsing
object model, maybe that part doesn't recognize the namespace declaration
That xmlns="http://purl.org/atom/ns#" is default namespace declaration.
That means feed element and all its descendants elements are in
"http://purl.org/atom/ns#" namespace.
Right
Read about default namespace and XPath (there was good article at
Extreme XML column a couple of years ago)
I know, I've read it sometimes ago
and take a look at
XPathNavigator.Select(XPathExpression) method documentation for a sample
of selecting nodes with default namespace involved.

I try to "wire in" the namespace declaration, thanks!

--
Lawrence
" It's probably for the best. What use does Microsoft have for an employee
who knows the W3C standards?"
-- an anonymous about tantek departure from microsoft