Microsoft released today the latest update to its .NET runtime environment, bringing to a close several years of development on some of the more significant additions to the framework, including enhancements to the C# language:

NET Framework 3.5 builds incrementally on the new features added in .NET Framework 3.0. For example, feature sets in Windows Workflow Foundation (WF), Windows Communication Foundation (WCF), Windows Presentation Foundation (WPF) and Windows CardSpace. In addition, .NET Framework 3.5 contains a number of new features in several technology areas which have been added as new assemblies to avoid breaking changes. They include the following:

• Deep integration of Language Integrated Query (LINQ) and data awareness. This new feature will let you write code written in LINQ-enabled languages to filter, enumerate, and create projections of several types of SQL data, collections, XML, and DataSets by using the same syntax.
• ASP.NET AJAX lets you create more efficient, more interactive, and highly-personalized Web experiences that work across all the most popular browsers.
• New Web protocol support for building WCF services including AJAX, JSON, REST, POX, RSS, ATOM, and several new WS-* standards.

New classes in .NET Framework 3.5 base class library (BCL) that address many common customer requests.

• Full tooling support in Visual Studio 2008 for WF, WCF, and WPF, including the new workflow-enabled services technology.

Scott Guthrie, manager of Microsoft's developer tools division, highlights many new language features added to the latest version of C# that also ships with the current release:

• Automatic Properties, Object Initializer and Collection Initializers
• Extension Methods
• Lambda Expressions
• Query Syntax
• Anonymous Types

One of the most anticipated new .NET features is LINQ. Guthrie also points to more information about this O/R mapping technology:

LINQ to SQL is a built-in OR/M (object relational mapper) in .NET 3.5. It enables you to model relational databases using a .NET object model. You can then query the database using LINQ, as well as update/insert/delete data from it. LINQ to SQL fully supports transactions, views, and stored procedures. It also provides an easy way to integrate business logic and validation rules into your data model.

Key additions to Visual Studio include Ajax support, including intelligent coding hints for JavaScript, and support for all the new .NET 3.5 features. Microsoft also released free "Express" versions of individual Visual Studio tools.

What do you think of the new features of .NET 3.5?