LINQ Pocket Reference

Instantiating an X-DOM

Rather than use the Load or Parse methods, you can build an X-DOM tree by manually instantiating objects and adding them to a parent via XContainer ’s Add method.

To construct an XElement and XAttribute, you simply provide a name and value:

	XElement lastName = new XElement ("lastname", "Bloggs");
	lastName.Add (new XComment ("nice name"));

	XElement customer = new XElement ("customer");
	customer.Add (new XAttribute ("id", 123));
	customer.Add (new XElement ("firstname", "Joe"));
	customer.Add (lastName);

	Console.WriteLine (customer.ToString());

The result:

	<customer id="123">
	  <firstname>Joe</firstname>
	  <lastname>Bloggs<!--nice name -></lastname>
	</customer>

A value is optional when constructing an XElement—you can provide just the element name and add content later. Notice that when we did provide a value, a simple string sufficed— we didn’t need to explicitly create and add an XText child node. The X-DOM does this work automatically, so you can deal simply with “values.”

Functional Construction

In our preceding example, it’s hard to glean the XML structure from the code. X-DOM supports another mode of instantiation called functional construction (from functional programming). With functional construction, you build an entire tree in a single expression:

	XElement customer =
	  new XElement ("customer", new XAttribute("id", 123),
	    new XElement ("firstname","joe"),
	    new XElement ("lastname","bloggs",
	      new XComment ("nice name")
	    )
	  );

This has two benefits. First, the code resembles ...