Welcome to the Microsoft .NET Framework version 3.5. The .NET Framework is a technology that supports building and running the next generation of applications and Web services. The .NET Framework consists of the common language runtime (CLR) and the .NET Framework class library, which includes ADO.NET, ASP.NET, Windows Forms, and Windows Presentation Foundation (WPF). The .NET Framework provides a managed execution environment, simplified development and deployment, and integration with a wide variety of programming languages.
You can download the .NET Framework 3.5 from the Microsoft Download Center. (To use the .NET Framework 3.5 on Windows 8, you must enable it on your computer. For instructions, see Installing the .NET Framework 3.5 on Windows 8.)
For a brief introduction to the architecture of the .NET Framework, see .NET Framework Conceptual Overview. For a discussion of .NET Framework version 3.5 and its relationship to previous versions of the .NET Framework, see .NET Framework 3.5 Architecture.
The documentation for the .NET Framework includes an extensive class library reference, conceptual overviews, step-by-step procedures, and information about samples, compilers, and command-line tools. To locate the information that interests you, see the following list of main topic areas.
- .NET Framework Class Library
Supplies syntax, code examples, and related information for each class contained in the .NET Framework namespaces.
- Quick Technology Finder
Provides a table of links to the main technology areas of the .NET Framework.
- What's New in the .NET Framework
Describes key features that have been added or modified in the latest versions of the .NET Framework.
- Overview of the .NET Framework
Describes key .NET Framework concepts such as the common language runtime, the common type system (CTS), cross-language interoperability, managed execution, assemblies, and security.
- Core Development Technologies
Explains common programming tasks that apply to a range of .NET Framework applications. Includes topics such as accessing data, file and stream I/O, configuration, encoding, deployment, and debugging.
- Advanced Development Technologies
Provides information about sophisticated development tasks and techniques in the .NET Framework.
- Security in the .NET Framework
Provides information about the classes and services in the .NET Framework that facilitate secure application development.
- ASP.NET Portal
Provides links to documentation about ASP.NET applications, Web Forms, and Web services.
- Windows Forms Portal
Provides links to documentation about common programming tasks in Windows Forms applications.
- .NET Compact Framework
Introduces the .NET Framework-based, hardware-independent environment for running applications on resource-constrained computing devices.
- Windows Presentation Foundation
Provides information about developing applications using Windows Presentation Foundation (WPF).
- Windows Communication Foundation for Applications
Provides information on the Windows Communication Foundation (WCF) programming model for building service-oriented applications.
- Windows CardSpace
Provides information about CardSpace, which is Microsoft's implementation of an identity metasystem.
- Windows Workflow Foundation
Provides information on the framework, programming model, and tools for Windows Workflow Foundation (WF).
- General Reference for the .NET Framework
Provides reference information related to the .NET Framework. Includes sections on languages and compilers, tools, technical references, and a glossary of terms.
- Tools (.NET Framework)
Provides information about tools that make it easier for you to create, deploy, and manage applications and components that target the .NET Framework.
- Samples (.NET Framework Technologies)
Provides samples that illustrate various aspects of the .NET Framework.