News

First Source Code for .NET Framework Libraries Released

Microsoft releases .NET 3.5 Framework library source code.

Microsoft has followed up on its promise to release the .NET 3.5 Framework library source code.

Libraries Now Open

A list of what's available for developers to view:
  • .NET Base Class Libraries (including System, System.CodeDom, System.Collections, System.ComponentModel, System.Diagnostics, System.Drawing, System.Globalization, System.IO, System.Net, System.Reflection, System.Runtime, System.Security, System.Text, System.Threading, etc.)
  • .ASP.NET (System.Web, System.Web.Extensions)
  • Windows Forms (System.Windows.Forms)
  • Windows Presentation Foundation (System.Windows)
  • ADO.NET and XML (System.Data and System.Xml)
Source: Microsoft
The company released the source code of more than a dozen libraries -- including ASP.NET, Windows Presentation Layer, Windows Forms and the .NET Base Class Libraries -- last month (see "Libraries Now Open").

Scott Guthrie, general manager of the Microsoft Developer Division, is promising that more libraries will come soon, including ones for Workflow, Windows Communication Foundation and LINQ.

"We think that enabling source code access and debugger integration of the .NET Framework libraries is going to be really valuable for .NET developers," he says in his blog post announcing the release of the class libraries. "Being able to step through and review the source should provide much better insight into how the .NET Framework libraries are implemented, and in turn enable you to build better applications and make even better use of them."

His blog includes instructions for configuring Visual Studio 2008 to access and debug the source code.

While the source code is being released under the company's read-only reference license (as originally planned), Guthrie notes Microsoft has made a change to the license terms.

"When we announced that we were releasing the source code back in October, some people had concerns about the potential impact of their viewing the source," notes Guthrie. Now, if a developer is coding for the Windows platforms, "You can look at the code, even if that software has 'the same or substantially the same features or functionality' as the .NET Framework," he says.

About the Author

Becky Nagel serves as vice president of AI for 1105 Media specializing in developing media, events and training for companies around AI and generative AI technology. She also regularly writes and reports on AI news, and is the founding editor of PureAI.com. She's the author of "ChatGPT Prompt 101 Guide for Business Users" and other popular AI resources with a real-world business perspective. She regularly speaks, writes and develops content around AI, generative AI and other business tech. She has a background in Web technology and B2B enterprise technology journalism.

comments powered by Disqus

Featured

  • Mastering Blazor Authentication and Authorization

    At the Visual Studio Live! @ Microsoft HQ developer conference set for August, Rockford Lhotka will explain the ins and outs of authentication across Blazor Server, WebAssembly, and .NET MAUI Hybrid apps, and show how to use identity and claims to customize application behavior through fine-grained authorization.

  • Linear Support Vector Regression from Scratch Using C# with Evolutionary Training

    Dr. James McCaffrey from Microsoft Research presents a complete end-to-end demonstration of the linear support vector regression (linear SVR) technique, where the goal is to predict a single numeric value. A linear SVR model uses an unusual error/loss function and cannot be trained using standard simple techniques, and so evolutionary optimization training is used.

  • Low-Code Report Says AI Will Enhance, Not Replace DIY Dev Tools

    Along with replacing software developers and possibly killing humanity, advanced AI is seen by many as a death knell for the do-it-yourself, low-code/no-code tooling industry, but a new report belies that notion.

  • Vibe Coding with Latest Visual Studio Preview

    Microsoft's latest Visual Studio preview facilitates "vibe coding," where developers mainly use GitHub Copilot AI to do all the programming in accordance with spoken or typed instructions.

  • Steve Sanderson Previews AI App Dev: Small Models, Agents and a Blazor Voice Assistant

    Blazor creator Steve Sanderson presented a keynote at the recent NDC London 2025 conference where he previewed the future of .NET application development with smaller AI models and autonomous agents, along with showcasing a new Blazor voice assistant project demonstrating cutting-edge functionality.

Subscribe on YouTube