Posted By: Anonymous
I am now learning
XmlDocument but I’ve just ran into
XDocument and when I try to search the difference or benefits of them I can’t find something useful, could you please tell me why you would use one over another ?
If you’re using .NET version 3.0 or lower, you have to use
XmlDocument aka the classic DOM API. Likewise you’ll find there are some other APIs which will expect this.
If you get the choice, however, I would thoroughly recommend using
XDocument aka LINQ to XML. It’s much simpler to create documents and process them. For example, it’s the difference between:
XmlDocument doc = new XmlDocument(); XmlElement root = doc.CreateElement("root"); root.SetAttribute("name", "value"); XmlElement child = doc.CreateElement("child"); child.InnerText = "text node"; root.AppendChild(child); doc.AppendChild(root);
XDocument doc = new XDocument( new XElement("root", new XAttribute("name", "value"), new XElement("child", "text node")));
Namespaces are pretty easy to work with in LINQ to XML, unlike any other XML API I’ve ever seen:
XNamespace ns = "http://somewhere.com"; XElement element = new XElement(ns + "elementName"); // etc
LINQ to XML also works really well with LINQ – its construction model allows you to build elements with sequences of sub-elements really easily:
// Customers is a List<Customer> XElement customersElement = new XElement("customers", customers.Select(c => new XElement("customer", new XAttribute("name", c.Name), new XAttribute("lastSeen", c.LastOrder) new XElement("address", new XAttribute("town", c.Town), new XAttribute("firstline", c.Address1), // etc ));
It’s all a lot more declarative, which fits in with the general LINQ style.
Now as Brannon mentioned, these are in-memory APIs rather than streaming ones (although
XStreamingElement supports lazy output).
XmlWriter are the normal ways of streaming XML in .NET, but you can mix all the APIs to some extent. For example, you can stream a large document but use LINQ to XML by positioning an
XmlReader at the start of an element, reading an
XElement from it and processing it, then moving on to the next element etc. There are various blog posts about this technique, here’s one I found with a quick search.