How to create an XDocument given an XmlWriter?

Question

We have a method that writes XML into an XmlWriter, we use this to generate a stream of XML directly without having to go via some form of DOM. However there are occasions where we do want to create a DOM. One approach would be to always build a DOM and to stream from that (to cover both requirements), but we like the performance of writing XML directly. Therefore we want to build a DOM from an XmlWriter.

See How to create a XmlDocument using XmlWriter in .NET? for an example of how to create an XmlDocument from an XmlWriter, albeit using a slightly off-piste code pattern. Are there similar options if I want an XDocument (or XElement subtree) instead?

Answer 1

Have a look at the XContainer.CreateWriter Method:

XContainer.CreateWriter Method

Creates an XmlWriter that can be used to add nodes to the XContainer.

Both XDocument and XElement are XContainers.

Example:

XDocument doc = new XDocument();
using (XmlWriter writer = doc.CreateWriter())
{
    // Do this directly 
    writer.WriteStartDocument();
    writer.WriteStartElement("root");
    writer.WriteElementString("foo", "bar");
    writer.WriteEndElement();
    writer.WriteEndDocument();
    // or anything else you want to with writer, like calling functions etc.
}