I just learnt something new and cool from one of Scott Guthries blogs: the ?? null coalescing operator in C# 2.0. I never noticed it until now, and actually thought it was part of 3.0, until a kind reader corrected me... it's been around ever since the advent of nullable types in C#.

Basically, this operator works like the T-SQL ISNULL or COALESCE function. Read all about it in Scott's blog!

I recently installed the RTM version of Visual Studio 2008 (previously known as Orcas), which comes with C# 3.0 and .NET Framework 3.5. One of the coolest new things is LINQ, more on that in my next blog. The next coolest thing is the new C# 3.0 language support for lambda expressions, see the node  => part below:

XmlHelper.Visit(_rootTOCItem.ParentNode, "tocitem", 

  node => _tocItems.Add((XmlElement)node));

Where _tocItems is a List<XmlElement>  stored in the class that is calling this method.

This works because Visit accepts a delegate, and I am passing in an anonymous delegate above using the new syntax. Visit is just something I wrote that iterates over the nodes in an Xml tree. I could have used Link to Xml for that part, but this is a tree of XmlElements returned by an XmlDataProvider, and Linq to Xml operates on XElements.

public class XmlHelper

{

  public delegate void NodeVisitor(XmlNode node);

  public static void Visit( XmlNode node, string nodeNameFilter, NodeVisitor visitor )

  {

    if ( node.Name==nodeNameFilter)

      (node);

    if (node.HasChildNodes)

      foreach (XmlNode child in node.ChildNodes)

        (child, nodeNameFilter, visitor);

  }

}