How to add Namespace and Declaration in XDocument

Question

I am creating xml in C#, and want to add Namespace and Declaration . My xml as below:

XNamespace ns = "http://ab.com//abc";

XDocument myXML = new XDocument(
    new XDeclaration("1.0","utf-8","yes"),
    new XElement(ns + "Root",
        new XElement("abc","1")))

This will add xmlns="" at both Root level and child element abc level as well.

<Root xmlns="http://ab.com/ab">
    <abc xmlns=""></abc>
</Root>

But I want it in only Root level not in child level like below:

<Root xmlns="http://ab.com/ab">
    <abc></abc>
</Root>

and how to add Declaration at Top, my code not showing Declaration after run.

Please help me to get the complete xml as

<?xml version="1.0" encoding="UTF-8" standalone="yes" ?>
<Root xmlns="http://ab.com/ab">
    <abc></abc>
</Root>

score 2 · Accepted Answer · edited May 23 '17 at 11:51

You need to use the same namespace in your child elements:

XDocument myXML = new XDocument(
    new XDeclaration("1.0","utf-8","yes"),
        new XElement(ns + "Root",
            new XElement(ns + "abc", "1")))

If you just use "abc" this will be converted to an XName with no Namespace. This then results in an xmlns="" attribute being added so the fully qualified element name for abc would be resolved as such.

By setting the name to ns + "abc" no xmlns attribute will be added when converted to string as the default namespace of http://ab.com/ab is inherited from Root.

If you wanted to simply 'inherit' the namespace then you wouldn't be able to do this in such a fluent way. You'd have create the XName using the namespace of the parent element, for example:

 var root = new XElement(ns + "Root");
 root.Add(new XElement(root.Name.Namespace + "abc", "1"));

Regarding the declaration, XDocument doesn't include this when calling ToString. It will if you use Save to write to a Stream, TextWriter, or if you supply an XmlWriter that doesn't have OmitXmlDeclaration = true in its XmlWriterSettings.

If you wanted to just get the string, this question has an answer with a nifty extension method using a StringWriter.

Thanks for the answer. If i dont want to refer namespace in child element then how to implement ? — user1893874, Jun 01 '15 at 18:18
@user1893874 there's no easy way, I've added a possible option. How you apply this depends on the wider context of your code. — Charles Mager, Jun 01 '15 at 18:21

score 0 · Answer 2 · answered Jun 01 '15 at 18:01

0

Use the namespace on all elements you create:

XDocument myXML = new XDocument(
                  new XDeclaration("1.0","utf-8","yes"),
                  new XElement(ns + "Root",
                     new XElement(ns + "abc","1")))

answered Jun 01 '15 at 18:01

Martin Honnen

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Thanks for the answers. cant i add namespace only to the Root element ? – user1893874 Jun 01 '15 at 18:12

How to add Namespace and Declaration in XDocument

2 Answers2