Retrieve namespaces from xml document

[Daniele]

Hi all,

We are developing a .net application that can accept xml documents.

Every xml document can match a single schema, or it may be composed by
multiple different elements and each of these can match a different xsd
schema.

Is there a way to retrieve the namespace collection of all the document
namespaces for which there is at least one element in the document?

Example:

<?xml version="1.0" encoding="utf-8"?>

<xv:MainDocument xmlns:cc="http://tempuri.org/Customer.xsd"
xmlns:xv="http://tempuri.org/Product.xsd"
xmlns:xf="http://tempuri.org/Order.xsd">

<cc:Customer>

<cc:CustomerCode>EFEREFFF</cc:CustomerCode>

<cc:BusinessName>fg sdg sdgh sgfhsdgh sdfg</cc:BusinessName>

<cc:Address>asdfsdf asdf asdf </cc:Address>

<cc:ZipCode>32323</cc:ZipCode>

<cc:CountryCode>IT</cc:CountryCode>

<cc:ProvinceCode>TV</cc:ProvinceCode>

<cc:PricelistCode>PR1</cc:PricelistCode>

</cc:Customer>

<xv:Product>

<xv:ProductCode></xv:ProductCode>

<xv:Price>120.00</xv:Price>

</xv:Product>

</xv:MainDocument>

For example, in this XML document there are two elements matching two
different xsd schemas. For this document We want to retrieve the namespaces
"http://tempuri.org/Customer.xsd" and http://tempuri.org/Product.xsd"

Thanks in advance,

Daniele_

[Oleg Tkachenko [MVP]]

Daniele wrote:

Is there a way to retrieve the namespace collection of all the document
namespaces for which there is at least one element in the document?

Well, that's easy, but what's the best way depend on your application.
Perf and memory friendly way is to collect namespaces using simple
custom XmlReader, while XML is being read. Otherwise it can be done
easily using XSLT.
--
Oleg Tkachenko [XML MVP]
http://blog.tkachenko.com

[Albertone]

"Oleg Tkachenko [MVP]" <oleg@NO!SPAM!PLEASEtkachenko.com> wrote in message
news:OU**************@TK2MSFTNGP09.phx.gbl...

Daniele wrote:

Is there a way to retrieve the namespace collection of all the document
namespaces for which there is at least one element in the document?
Well, that's easy, but what's the best way depend on your application.
Perf and memory friendly way is to collect namespaces using simple
custom XmlReader, while XML is being read. Otherwise it can be done
easily using XSLT.

Have you any helpful examples?
Thanks, Alberto.
--
Oleg Tkachenko [XML MVP]
http://blog.tkachenko.com

[Oleg Tkachenko [MVP]]

Albertone wrote:

Have you any helpful examples?

Here is simple custom XmlReader:

public class NamespaceCllectingXmlReader : XmlTextReader
{
Hashtable namespaces = new Hashtable();

//Add constructors as needed
public NamespaceCllectingXmlReader(string url) : base(url) {}

public Hashtable CollectedNamespaces
{
get { return namespaces; }
}

public override bool Read()
{
bool baseRead = base.Read();
if (base.NodeType == XmlNodeType.Element && base.NamespaceURI
!= ""
&& !namespaces.ContainsKey(base.NamespaceURI))
namespaces.Add(base.NamespaceURI, "");
return baseRead;
}
}

and here is its usage:

XmlDocument doc = new XmlDocument();
NamespaceCllectingXmlReader ncr = new
NamespaceCllectingXmlReader("foo.xml");
doc.Load(ncr);
foreach (object ns in ncr.CollectedNamespaces.Keys)
Console.WriteLine(ns);

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

[Albertone]

Ok Oleg, your code seems to work fine.
Thanks, Alberto.

"Oleg Tkachenko [MVP]" <oleg@NO!SPAM!PLEASEtkachenko.com> wrote in message
news:#i*************@tk2msftngp13.phx.gbl...

Albertone wrote:

Have you any helpful examples?

Here is simple custom XmlReader:

public class NamespaceCllectingXmlReader : XmlTextReader
{
Hashtable namespaces = new Hashtable();

//Add constructors as needed
public NamespaceCllectingXmlReader(string url) : base(url) {}

public Hashtable CollectedNamespaces
{
get { return namespaces; }
}

public override bool Read()
{
bool baseRead = base.Read();
if (base.NodeType == XmlNodeType.Element && base.NamespaceURI
!= ""
&& !namespaces.ContainsKey(base.NamespaceURI))
namespaces.Add(base.NamespaceURI, "");
return baseRead;
}
}

and here is its usage:

XmlDocument doc = new XmlDocument();
NamespaceCllectingXmlReader ncr = new
NamespaceCllectingXmlReader("foo.xml");
doc.Load(ncr);
foreach (object ns in ncr.CollectedNamespaces.Keys)
Console.WriteLine(ns);

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

[Daniele]

"Oleg Tkachenko [MVP]" <oleg@NO!SPAM!PLEASEtkachenko.com> wrote in message
news:%2***************@tk2msftngp13.phx.gbl...

Albertone wrote:

Have you any helpful examples?

Here is simple custom XmlReader:

public class NamespaceCllectingXmlReader : XmlTextReader
... Oleg Tkachenko [XML MVP]

Oh yeah, this works fine!
In previous message you say something about XSLT. It could be faster? Excuse
me if I put this question, but I am a newbie with XML and I don't know well
XSLT syntax... Maybe you have an example with XSLT?
Thank you.

[Oleg Tkachenko [MVP]]

Daniele wrote:

Oh yeah, this works fine!
In previous message you say something about XSLT. It could be faster? Excuse
me if I put this question, but I am a newbie with XML and I don't know well
XSLT syntax... Maybe you have an example with XSLT?

In XSLT it's going to be something like

<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:key name="nsKey" match="*" use="namespace-uri()"/>
<xsl:template match="/">
<xsl:for-each select="//*[generate-id() = generate-id(key('nsKey',
namespace-uri())[1])]">
<xsl:value-of select="namespace-uri()"/>
</xsl:for-each>
</xsl:template>
</xsl:stylesheet>

but it won't be faster XmlReader anyway. It requires at least two full
XML tree traversals.

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