Getting Started

Download .NET Framework 3.5 SP1

The .NET Framework 3.5 Service Pack 1 (SP1) delivers more controls, improved start-up performance, AJAX support, and powerful new graphics features for client development. Visit the .NET Framework downloads page for more information.

Try out .NET Framework 4. Download Beta 2 today.

.NET Framework Technologies

Windows Presentation Foundation (WPF)
Use WPF for building applications and high fidelity experiences in Windows Vista.

Windows Communication Foundation (WCF)
Use WCF for building and running connected systems.

Windows Workflow Foundation (WF)
Use WF for building workflow-enabled applications on Windows.

Windows Forms
Use Windows Forms for building smart client applications.

Base Class Libraries (BCL)
The BCL provides the fundamental building blocks for any application.

.NET Services
Use .NET Services to connect cloud-based and cloud-aware applications.

ASP.NET
ASP.NET is a free technology for building dynamic web applications.

ADO.NET
Use ADO.NET to access data sources such as Microsoft SQL Server, OLE DB, and XML.

Common Language Runtime (CLR)
The CLR is the .NET Framework run-time environment.

Windows CardSpace
Windows CardSpace provides the consistent user experience required by the identity metasystem.

.NET Compact Framework
Use .NET Compact Framework to build applications for Windows CE-based devices.

.NET Micro Framework
Use the .NET Micro Framework to develop for resource-constrained devices.

.NET Framework Highlights

CLR Inside Out: Exploring the .NET Framework 4 Security Model
The .NET Framework 4 introduces many updates to the .NET security model that make it much easier to host, secure and provide services to partially trusted code.
.NET Framework 4 Poster
This poster highlights some of the most important namespaces and classes in the .NET Framework 4. The purpose is to highlight the most important changes and new features for developers in .NET Framework 4.
Give Us Your Feedback on Visual Studio Documentation
Help us help you by taking 10 minutes to fill out our Visual Studio Content Survey on how to improve the Visual Studio documentation.

Featured Library Content

Important updates and highlights of .NET Framework content in the MSDN Library.

XAML Overview
New to XAML in WPF or need a refresher? This topic discusses how you can use XAML to write WPF ap... 詳細情報
Monday, Oct 26 - Microsoft
How to: Compress and Decompress Files
Provides an updated code example for compressing and decompressing data. Compression works better fo... 詳細情報
Thursday, Oct 15 - Microsoft
Windows Presentation Foundation Community Feedback
Learn about the various ways you can interact with other users of WPF and developers from Microsoft.
Friday, Oct 9 - Microsoft

More .NET Framework Library Content...

More .NET Framework Resources

Get .NET Framework 4 Beta 2Get .NET Framework 4 Beta 2

.NET Framework 4 and Visual Studio 2010 mark the next generation of developer tools from Microsoft. Be sure to download Beta 2 and let us know what you think.

Give Us Your Feedback on .NET Framework DocumentationGive Us Your Feedback on .NET Framework Documentation

Help us help you by taking 10 minutes to fill out our Content Survey on how to improve the Visual Studio and .NET Framework documentation.

Channel 9 Videos for .NET FrameworkChannel 9 Videos

Watch videos and connect with your peers.

.NET Code Gallery Samples for .NET FrameworkCode Gallery

Find the latest .NET code samples or upload your own.

.NET Projects on CodePlexCodePlex

Find open source projects on CodePlex or start your own.

.NET in MSDN Magazine MSDN Magazine

Read in-depth articles about .NET.

patterns & practicespatterns & practices

Use Microsoft's proven practices for software engineering.
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