Default namespace, prefix and XDocument

  • Thread starter Thread starter Ilyas
  • Start date Start date
I

Ilyas

Hi all

I have the following code:

Namespace ns = "http://www.abc.com";
XDocument xDoc = new XDocument(
new XElement(ns + "root",
new XElement("person",
new XAttribute("id", 1),
new XElement("forename", "jack"),
new XElement("age", 35)),
new XElement("person",
new XAttribute("id", 2),
new XElement("forename", "bob"),
new XElement("age", 2)
)));

This is the xml written if I do Console.WriteLine(xDoc):
<root xmlns="http://www.abc.com">
<person id="1" xmlns="">
<forename>jack</forename>
<age>35</age>
</person>
<person id="2" xmlns="">
<forename>bob</forename>
<age>2</age>
</person>
</root>

However why do both person elements have a blank for xmlns. I would
have though that would have not been there....can anyone explain. How
do I get rid of the xmlns='' ?

What I want is if no namespace is specified then my xml elements
should be in the default namespace (http://www.abc.com) - how can
Imodify the above code so I dont end up with xmlns='' in the person
tags...?

Thanks
 
Ilyas said:
What I want is if no namespace is specified then my xml elements
should be in the default namespace (http://www.abc.com) - how can
Imodify the above code so I dont end up with xmlns='' in the person
tags...?
Click to expand...

When you create XML with namespace programmatically the namespace of
each element or attribute node is determined when you create it. If you
want an element "foo" to be in a certain namespace (stored in variable
ns) you need to use e.g.
new XElement(ns + "foo")
each time you create an element. So you need

Namespace ns = "http://www.abc.com";
XDocument xDoc = new XDocument(
new XElement(ns + "root",
new XElement(ns + "person",
new XAttribute("id", 1),
new XElement(ns + "forename", "jack"),
new XElement(ns + "age", 35)),
new XElement(ns + "person",
new XAttribute("id", 2),
new XElement(ns + "forename", "bob"),
new XElement(ns + "age", 2)
)));

If you only do
new XElement("foo")
then you create an element with local name "foo" in _no_ namespace and
that way the serialization needs to add xmlns="" if an ancestor is in a
namespace.
 
When you create XML with namespace programmatically the namespace of
each element or attribute node is determined when you create it. If you
want an element "foo" to be in a certain namespace (stored in variable
ns) you need to use e.g.
   new XElement(ns + "foo")
each time you create an element. So you need

Namespace ns = "http://www.abc.com";
             XDocument xDoc = new XDocument(
                 new XElement(ns + "root",
                     new XElement(ns + "person",
                         new XAttribute("id", 1),
                         new XElement(ns + "forename", "jack"),
                         new XElement(ns + "age", 35)),
                     new XElement(ns + "person",
                         new XAttribute("id", 2),
                         new XElement(ns + "forename", "bob"),
                         new XElement(ns + "age", 2)
                     )));

If you only do
   new XElement("foo")
then you create an element with local name "foo" in _no_ namespace and
that way the serialization needs to add xmlns="" if an ancestor is in a
namespace.
Click to expand...

Okay that makes sense what youre saying - My thought was that If I
dont specify a namespace, then my element would be in the default
namespace (in this case http://www.abc.com), but that doesnt seem to
be the case.

It makes the code look a bit ugly with all this namespace
concatenation too - is there anyway I can get around that, perhaps by
using a different method/approch altogether?
 
Ilyas said:
Okay that makes sense what youre saying - My thought was that If I
dont specify a namespace, then my element would be in the default
namespace (in this case http://www.abc.com), but that doesnt seem to
be the case.
Click to expand...

You have to distinguish between writing or authoring XML and creating it
programmatically. If you write/author

<root xmlns="http://example.com/">
<foo>
<bar/>
</foo>
</root>

then the default namespace declaration on the 'root' element applies to
its descendant elements ('foo', 'bar') as well.

However when you create elements programmatically they get their
namespace when you create them and don't change them or adapt them
depending on any parent or ancestor you add them to.

It makes the code look a bit ugly with all this namespace
concatenation too - is there anyway I can get around that, perhaps by
using a different method/approch altogether?
Click to expand...

The LINQ to XML API does not have anything as far as I know, you would
have to write your own. With VB.NET you can use XML literals and define
a namespace at the beginning of your module with e.g.
Imports <xmlns="http://example.com/">
 
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