XDocument or XmlDocument

Question

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 ?

Accepted Answer

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);
```

and

```
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). `XmlReader` and `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.

XDocument or XmlDocument

Solution

Problem

Related problems