We’ve moved our sights from Rack to LINQ. That is, we don’t want to only support other ORMs—we want Ambition to be a query language for SQL, LDAP, XPath, the works. The 1.0 release will be backend-agnostic. Maybe then we’ll change the name to Hubris? Time will tell.

XElement highriseRoot = XElement.Load("highrise-contact.xml");

We use the static Load method of XElement to load the XML contained within the "highrise-contact.xml" file that we've saved locally. I don't believe the Highrise API is officially supported at the moment so I'm not going to load the contact details directly from the highrisehq.com site. Perhaps, in a future post we can explore that as an option.

Anywho, once our XML is loaded into an XElement, we can transform our Highrise XML into the hCard microformat by building a new XElement. We'll use the Element query axis method to retrieve the first and last name of the contact, and we'll embed query expressions and make use of the Descendants query axis method for selecting all the email and web addresses for the contact within the source XML. When we put it all together we end up with the C# code below:

XElement highriseRoot = XElement.Load("highrise-contact.xml");

XElement hCard =
    new XElement("div",
        new XAttribute("class", "vcard"),
        new XElement("div",
            new XAttribute("class", "fn"),
            highriseRoot.Element("first-name") + " " + highriseRoot.Element("last-name")
        ),
        from emailElement in highriseRoot.Descendants("email-address")
        select new XElement("div",
            "Email:",
            new XElement("span",
                new XAttribute("class", "email"),
                (string) emailElement.Element("address")
            )
        ),
        from webElement in highriseRoot.Descendants("web-address")
        select
        new XElement("a",
            new XAttribute("class", "url"),
            new XAttribute("href", (string) webElement.Element("url")),
            (string) webElement.Element("url")
        )
    );

Console.WriteLine(hCard);

At first glance, the above code might be overwhelming. However, once you come to understand the power of functional construction you'll quickly realize how wonderful LINQ to XML can be for transforming XML to alternate XML formats. In addition to making it easy to transform XML into alternate XML formats, LINQ to XML also makes it very easy to transform XML into objects. If we have a Contact class defined as:

public class Contact {
    public string Name { get; set; }
    public IEnumerable<string> EmailAddresses { get; set; }
    public IEnumerable<string> Urls { get; set; }
}

We can transform the contact details in our XML into a Contact instance with the following code:

Contact contact = new Contact {
    Name = (string) highriseRoot.Element("first-name") + " " + (string) highriseRoot.Element("last-name"),
    EmailAddresses = highriseRoot.Descendants("email-address").Select(e => (string)e.Element("address")),
    Urls = highriseRoot.Descendants("web-address").Select(e => (string)e.Element("url"))
};

After looking back at the sample here I wish I had chosen an XML fragment with a little more hierarchy, however it's much too late for that now. Hopefully, the code included in this post gives you a small taste of the types of XML transformations possible with LINQ to XML. As you begin to work with LINQ to XML, you'll find that functional construction, combined with query axis methods, and query expressions provide a tremendous amount of flexibility for transforming XML. Additionally, the new object initializer syntax and LINQ to XML's ability to easily construct objects from XML makes it very easy to create objects from XML. I've attached a zip file with the code above to this post. (VS2008 Beta 2 Required) LINQtoXMLTransformSample.zip (23.69 KB)

• Functional Construction: Have you ever created XML using existing .NET XML API's?  Enough said, functional construction beats the pants out of anything else out there for creating XML.
• Powerful Transformation capabilities: By combining the powerful querying capabilities of LINQ with the functional construction pattern for XML creation LINQ to XML provides a lot of really nice transformation capabilities.  In addition to supporting superb XML to XML transformations, we also get killer support for transforming our XML into object structures, LINQ to SQL objects, and whatever else you can think up.
• LINQ: What else needs to be said, sprinkling LINQ query support on top of an XML API makes for a kick ass query experience.  We get the best of XPath and XQuery but in a much nicer, cleaner, and straightforward API.

• Implmenting Linq for NHibernate: A How to Guide Part 1
  
• Implementing Linq for NHibernate - Part 2 (Ordering and Paging)
• Implementing Linq for NHibernate - Part 3 (Aggregate and Element Operators)

• Attribute axis property is string
• Global Xml namespace syntax has changed
• Added auto-completion
• Xml names are VB symbols
• Improved error handling

The LINQ videos seem to be rolling out lately. 

• Wes Dyer interviews Charlie Calvert - download.
• Anders Hejlsberg on LINQ and Functional Programming

Boooooooooooooo! :)  I'd really like to get a new release that includes everything LINQ related that we saw in the May 2006 CTP so I can start updating all my code samples and use all the new wizz bang features that I'm sure they've added.

Update: I think I misread the post above.  The next Orcas CTP isn't being pushed to March, it's just a bunch of LINQ to SQL stuff that isn't making it into February that will show it's face in March.

• Mike has a nice post where he looks to Deconstruct LINQ.  I often find posts like Mike's, where the author is letting what they've learned flow out in a post, the most beneficial.
• Alex is considering a couple implementations of IQueryable, which he is calling LINQ to Web, that sound very useful.  I've been thinking about writing an implementation of LINQ to Google or LINQ to Live Search myself.  I have a feeling that a bunch of what Alex is after in LINQ to DOM could be handled with a couple extensions on top of LINQ to XML.
• There is a new video on Channel 9 with Anders Hejlsberg, Herb Sutter, Erik Meijer, Brian Beckman that is bound to be full of interesting topics.  I've been having some iPod video troubles lately and can't seem to find a good WMV to iPod Video Converter that runs on a Mac.  I should probably just do the video conversion in Parallels...ok started...can't wait to check it out.