Public Class XDocument _
    Inherits XContainer

Dim instance As XDocument

public class XDocument : XContainer

public ref class XDocument : public XContainer

public class XDocument extends XContainer

XDocument srcTree = new XDocument(
    new XComment("This is a comment"),
    new XElement("Root",
        new XElement("Child1", "data1"),
        new XElement("Child2", "data2"),
        new XElement("Child3", "data3"),
        new XElement("Child2", "data4"),
        new XElement("Info5", "info5"),
        new XElement("Info6", "info6"),
        new XElement("Info7", "info7"),
        new XElement("Info8", "info8")
    )
);

XDocument doc = new XDocument(
    new XComment("This is a comment"),
    new XElement("Root",
        from el in srcTree.Element("Root").Elements()
        where ((string)el).StartsWith("data")
        select el
    )
);
Console.WriteLine(doc);

Dim srcTree As XDocument = _ 
    <?xml version="1.0" encoding="utf-8" standalone="yes"?>
        <!--This is a comment-->
        <Root>
            <Child1>data1</Child1>
            <Child2>data2</Child2>
            <Child3>data3</Child3>
            <Child2>data4</Child2>
            <Info5>info5</Info5>
            <Info6>info6</Info6>
            <Info7>info7</Info7>
            <Info8>info8</Info8>
        </Root>
Dim doc As XDocument = _ 
    <?xml version="1.0" encoding="utf-8" standalone="yes"?>
        <!--This is a comment-->
        <Root>
            <%= From el In srcTree.<Root>.Elements _
                Where CStr(el).StartsWith("data") _
                Select el %>
        </Root>
Console.WriteLine(doc)

<!--This is a comment-->
<Root>
  <Child1>data1</Child1>
  <Child2>data2</Child2>
  <Child3>data3</Child3>
  <Child2>data4</Child2>
</Root>