下面的代码创建一个 XDocument 对象及其关联的包含对象。

using System.Xml.Linq;

XDocument d = new XDocument( 
　　new XComment("This is a comment."),　　new XProcessingInstruction("xml-stylesheet","href='mystyle.css' title='Compact' type='text/css'"),　　new XElement("Pubs",　　new XElement("Book",　　new XElement("Title","Artifacts of Roman Civilization"),　　new XElement("Author","Moreno,Jordao") 
　　),"Midieval Tools and Implements"),"Gazit,Inbar") 
　　) 
　　),　　new XComment("This is another comment.") 
　　); 
　　d.Declaration = new XDeclaration("1.0","utf-8","true"); 
　　Console.WriteLine(d); 
　　d.Save("test.xml");

<?xml version="1.0" encoding="utf-8"?>
<!--This is a comment.-->
<?xml-stylesheet href='mystyle.css' title='Compact' type='text/css'?>
<Pubs>
  <Book>
    <Title>Artifacts of Roman Civilization</Title>
    <Author>Moreno,Jordao</Author>
  </Book>
  <Book>
    <Title>Midieval Tools and Implements</Title>
    <Author>Gazit,Inbar</Author>
  </Book>
</Pubs>
<!--This is another comment.-->

构造 XML 树

　　XElement contacts = 
　　new XElement("Contacts",　　new XElement("Contact",　　new XElement("Name","Patrick Hines"),　　new XElement("Phone","206-555-0144"),　　new XElement("Address",　　new XElement("Street1","123 Main St"),　　new XElement("City","Mercer Island"),　　new XElement("State","WA"),　　new XElement("Postal","68042") 
　　) 
　　) 
　　);

另一个创建 XML 树的十分常用的方法是使用 LINQ 查询的结果来填充 XML 树，如下面的示例所示：

XElement srcTree = new XElement("Root",　　new XElement("Element",1),2),3),4),5) 
　　); 
　　XElement xmlTree = new XElement("Root",　　new XElement("Child",　　from el in srcTree.Elements() 
　　where (int)el > 2 
　　select el 
　　); 
　　Console.WriteLine(xmlTree);

此示例产生以下输出：

<Root>
  <Child>1</Child>
  <Child>2</Child>
  <Element>3</Element>
  <Element>4</Element>
  <Element>5</Element>
</Root>