Introduction

This article discusses the features introduced in Microsoft .Net Framework 2.0, 3.0, 3.5, 4.0, and the newly introduced 4.5 frameworks.

.Net Framework 2.0 Features

ADO.NET
New features in ADO.NET include support for user-defined types (UDT), asynchronous database operations, XML data types, large value types, snapshot isolation, and new attributes that allow applications to support multiple active result sets (MARS) with SQL Server 2005.
ASP.NET
The Microsoft .NET Framework 2.0 includes significant enhancements to all areas of ASP.NET. For Web page development, new controls make it easier to add commonly used functionality to dynamic Web pages. New data controls make it possible to display and edit data on an ASP.NET Web page without writing code. An improved code-behind model makes developing ASP.NET pages easier and more robust. Caching features provide several new ways to cache pages, including the ability to build cache dependency on tables in a SQL Server database.
ASP.NET accommodates a wide variety of browsers and devices. By default, controls render output that is compatible with XHTML 1.1 standards. You can use device filtering to specify different property values on the same control for different browsers.
.NET Remoting
.NET Framework Remoting now supports IPv6 addresses and the exchange of generic types. The classes in the System.Runtime.Remoting.Channels.TCP namespace support authentication and encryption using the Security Support Provider Interface (SSPI). Classes in the new System.Runtime.Remoting.Channels.IPC namespace allow applications on the same computer to communicate quickly without using the network. Finally, you can now configure the connection cache time-out and the number of method retries, which can improve the performance of network load-balanced remote clusters.
XML
The new System.Xml.XmlReaderSettings class allows the specification of the type of verifications to be done when using a subclass of XmlReader to read XML data.
It is now possible to partially validate a DOM tree loaded within an instance of XmlDocument.
It is now possible to modify a DOM tree stored in an XmlDocument instance through the XPathNavigator cursor API.

.Net Framework 3.0/3.5 Features

Windows Presentation Foundation (WPF)
Windows Presentation Foundation (WPF) is a next-generation presentation system for building Windows client applications. The core of WPF is a resolution-independent and vector-based rendering engine that is built to take advantage of modern graphics hardware.
WPF extends the core with a comprehensive set of application-development features that include Extensible Application Markup Language (XAML), controls, data binding, layout, 2-D and 3-D graphics, animation, styles, templates, documents, media, text, and typography. WPF is included in the Microsoft .NET Framework, so you can build applications that incorporate other elements of the .NET Framework class library.
To support some of the more powerful WPF capabilities and to simplify the programming experience, WPF includes additional programming constructs that enhance properties and events: dependency properties and routed events.
Windows Communication Foundation (WCF)
Windows Communication Foundation (WCF) is Microsoft's unified programming model for building service-oriented applications. WCF allows you to build many kinds of distributed applications including "traditional" Web Services so that your services support SOAP and will, therefore, be compatible with older .NET (and other) technologies. WCF is not just about pure SOAP over the wire - you can work with an Info set, and create a binary representation of your SOAP message that can then be sent along with your choice of protocol. This is for those who are particularly concerned about performance and have traditionally turned to .NET remoting.
Windows Workflow Foundation (WWF)
Windows Workflow Foundation, a core component of .NET Framework 3.0, provides a programming model, run-time engine, and tools for building workflow applications.
A workflow is created and maintained by the workflow run-time engine. There can be several workflow engines within an application domain, and each workflow engine can support multiple workflows running concurrently. The run-time enables idle workflows to be unloaded from memory, persisted to a store, and reloaded whenever input is received.
Workflows can be authored in code, XAML markup, or a combination of both, known as code-separation, which is similar to the ASP.NET mode.
Windows CardSpace (WCS)
Windows CardSpace (InfoCard) is a Digital Identity to online services. Digital Identity is how a user will be electronically represented. For a debit/credit card, each card has a digital identity and password. If any user uses the site on the internet then he enters their username and password, for identity, but this is not secure. WCS reduces these types of problems.
WCS (originally called Info Card) helps people keep track of their digital identities as distinct information cards. If a Web site accepts WCS logins, users attempting to log in to that site will see a WCS selection. By choosing a card, users also choose a digital identity that will be used to access this site. CardSpace and the new supporting technologies will change how you authenticate into an application, whether it sits on the Web, your phone, or your desktop.
Core New Features and Improvements
Some core new features and improvements are implemented in .Net 3.0/3.5; they are:
  1. Auto Implemented Property
  2. Implicit Typed local variable
  3. Implicitly Typed Arrays
  4. Anonymous Types
  5. Extension Methods (3.5 new feature)
  6. Object and Collection Initializers
  7. Lambda Expressions

.Net Framework 4.0 Features

Application Compatibility and Deployment
The .NET Framework 4 is highly compatible with applications that are built with earlier .NET Framework versions, except for some changes that were made to improve security, standards compliance, correctness, reliability, and performance.
The .NET Framework 4 does not automatically use its version of the common language runtime to run applications that are built with earlier versions of the .NET Framework. To run older applications with .NET Framework 4, you must compile your application with the target .NET Framework version specified in the properties for your project in Visual Studio, or you can specify the supported runtime with the <supportedRuntime> Element in an application configuration file.
Core New Features and Improvements
Some new features are introduced in the .Net framework 4.0.
The following sections describe new features and improvements provided by the common language runtime and the base class libraries.
  1. BigInteger and Complex Numbers
  2. Tuples
  3. Covariance and Contravariance
  4. Dynamic Language Runtime
Managed Extensibility Framework
The Managed Extensibility Framework (MEF) is a new library in the .NET Framework 4 that helps you build extensible and composable applications. MEF enables you to specify points where an application can be extended, to expose services to offer to other extensible applications and to create parts for consumption by extensible applications.
It also enables easy discoverability of available parts based on metadata, without the need to load the assemblies for the parts.
Parallel Computing
The .NET Framework 4 introduces a new programming model for writing multithreaded and asynchronous code that greatly simplifies the work of application and library developers. The new model enables developers to write efficient, fine-grained, and scalable parallel code in a natural idiom without having to work directly with threads or the thread pool. The new System.Threading.Tasks namespace and other related types support this new model.
Web
ASP.NET version 4 introduces new features in the following areas:
Windows Presentation Foundation (WPF) Features in 4.0
Windows Presentation Foundation (WPF) version 4 contains changes and improvements in the following areas:
Windows Communication Foundation Features in 4.0
Windows Communication Foundation (WCF) provides the following improvements:
Windows Workflow Foundation Features in 4.0
Windows Workflow Foundation (WF) provides improvements in the following areas:

.Net Framework 4.5 Features

.NET for Windows Store Apps
Windows Store apps are designed for specific form factors and leverage the power of the Windows operating system. A subset of the .NET Framework 4.5 is available for building Windows Store apps for Windows by using C# or Visual Basic.
Portable Class Libraries
The Portable Class Library project in Visual Studio 2012 enables you to write and build managed assemblies that work on multiple .NET Framework platforms. Using a Portable Class Library project, you choose the platforms (such as Windows Phone and .NET for Windows Store apps) to target.
ASP.NET 4.5
ASP.NET 4.5 includes the following new features:
Windows Presentation Foundation (WPF) Features in 4.5
In the .NET Framework 4.5, Windows Presentation Foundation (WPF) contains changes and improvements in the following areas:
Windows Communication Foundation (WCF) Features in 4.5
In the .NET Framework 4.5, the following features have been added to make it simpler to write and maintain Windows Communication Foundation (WCF) applications:
Windows Workflow Foundation (WF) Features in 4.5
Several new features have been added to Windows Workflow Foundation (WF) in the .NET Framework 4.5. These new features include:
References