Microsoft .NET Framework4

The Microsoft .NET Framework 4 provides the following new features and improvements:
The .NET Framework 4 works side by side with the Framework version 3.5 SP1. Applications that are based on earlier versions of the Framework will continue to run on that version. Just a subset of functionality is shared by all versions of the Framework.
Innovations in the Visual Basic and C# languages, for example statement lambdas, implicit line continuations, dynamic dispatch, and named/optional parameters.
The ADO.NET Entity Framework, which simplifies how developers program against relational databases by raising the level of abstraction, has many new features. These includes persistence ignorance and POCO support, lazy loading, test-driven development support, functions in model, and new LINQ operators.
Improvements to Windows Workflow (WF) that let developers to better host and interact with workflows. These include an improved activity programming model, an improved designer experience, a new flowchart modeling style, an expanded activity palette, workflow-rules integration, and new message correlation features. The .NET Framework also offers significant performance gains for WF-based workflows.
Additionally, .NET Framework 4 provides new WCF features such as service discovery, router service, simplified configuration and a number of improvements to queuing, REST support, diagnostics, and performance.