Setting xml namespaces with the System.Xml.Linq api

Question

Im having trouble generating XML along the lines of this:

<Root xmlns:brk="http://somewhere"&gt;
<child1>
     <brk:node1>123456</brk:node1>
     <brk:node2>500000000</brk:node2>
</child1>
</Root>

This code get me most of the way but I cant get the 'brk' namespace infront of the nodes;

 var rootNode = new XElement("Root");
 rootNode.Add(new XAttribute(XNamespace.Xmlns + "brk", "http://somewhere"));

 var childNode = new XElement("child1");
 childNode.Add(new XElement("node1",123456));
 rootNode.Add(childNode);

Iv tried this:

XNamespace brk = "http://somewhere";
childNode.Add(new XElement(brk+"node1",123456));

and this

XNamespace brk = "http://somewhere";
childNode.Add(new XElement("brk:node1",123456));

but both cause exceptions.

Answer 1

You are almost there, but you made one simple error in your first code example. I believe this is what you require:

XNamespace brk = "http://somewhere.com";
XElement root = new XElement("Root",
    new XAttribute(XNamespace.Xmlns + "brk", "http://somewhere.com"));

XElement childNode = new XElement("child1");
childNode.Add(new XElement(brk + "node1",123456));
root.Add(childNode);

The main difference here is where I add node1 to childNode as follows:

childNode.Add(new XElement(brk + "node1",123456));

This code, given an XmlWriter and XDocument gives me the output:

<?xml version="1.0" encoding="utf-8"?>
<Root xmlns:brk="http://somewhere.com"&gt;
  <child1>
    <brk:node1>123456</brk:node1>
  </child1>
</Root>

See MSDN for details of using XNamespace.

Answer 2

Seems odd that its fixed by setting up the namespace in the contrustor:

XElement root = new XElement("Root",
    new XAttribute(XNamespace.Xmlns + "brk", "http://somewhere.com"));

Adversed to using the add method:

var rootNode = new XElement("Root");
 rootNode.Add(new XAttribute(XNamespace.Xmlns + "brk", "http://somewhere"));

Slighty related how would I define a namespace like this:

<Root xsi:brr="http://somewhere.com"&gt;

</Root>

attempts such as this seem to also fail:

XNamespace xsi = "http://somewhere";
new XAttribute(xsi+"brr", @"http://somewhere");

This produces duplicate tag exception, and this:

new XAttribute("xsi:brr", @"http://somewhere");

Complains about the ':'