XD.md

What am I doing wrong here?

var ns = XNamespace.Xmlns + "guid";
var doc = new XDocument(
	new XElement("root",
		new XAttribute(ns, "Guid"),
		new XElement(ns + "MyValue", "{4258b6f1-2c60-4723-8d99-a458d05104b6}")));

// doc.ToString() throws an exception: Prefix "xmlns" is reserved for use by XML.

This is what I want to achieve:

<?xml version="1.0" ?>
<root xmlns:guid="Guid">
    <guid:MyValue>4258b6f1-2c60-4723-8d99-a458d05104b6</guid:MyValue>
</root>

     var doc = new XDocument(
          new XElement("root",
              new XAttribute(ns, "Guid"),
              new XElement(XName.Get("MyValue", "guid"), "{4258b6f1-2c60-4723-8d99-a458d05104b6}")));

Rather:

XNamespace desiredNs = "Guid";
var desiredPrefix = "guid";

var doc = new XDocument(
    new XElement("root",
    new XAttribute(XNamespace.Xmlns + desiredPrefix, desiredNs.NamespaceName),
    new XElement(desiredNs + "MyValue", "{4258b6f1-2c60-4723-8d99-a458d05104b6}")));

The other two comments result in <MyValue xmlns="guid"> which is likely not what you are after.

I see that because i want to see if you comment here too :-)

sorry
var doc = new XDocument(
new XElement("root",
new XAttribute(ns, "guid"),
new XElement(XName.Get("MyValue", "guid"), "{4258b6f1-2c60-4723-8d99-a458d05104b6}")));

@jcdickinson nailed it. FYI, Igal, you can also pass the guid value as a System.Guid instead of a string.

@mstrobel I know, but that's for a thing, and the thing has been there since vLegacy, and it has tests around it so... no :D