Microsoft .NET Framework 3.5 Library Source Code Now Available

Scott Guthrie[MSFT] announced the availability of .NET fx 3.5 library source code as promised. (Setup and how to use)

Quote from the announcement:

Specifically, you can now browse and debug the source code for the following .NET Framework libraries:

• .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)

We are in the process of adding additional framework libraries (including LINQ, WCF and Workflow) to the above list. I'll blog details on them as they become available in the weeks and months ahead.

[IMPORTANT] License Note:

First let's see what Scott said about it:

Reference License

The .NET Framework source is being released under a read-only reference license. When we announced that we were releasing the source back in October, some people had concerns about the potential impact of their viewing the source. To help clarify and address these concerns, we made a small change to the license to specifically call out that the license does not apply to users developing software for a non-Windows platform that has “the same or substantially the same features or functionality” as the .NET Framework. If the software you are developing is for 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.

Long story short:

The source code is meant to be used solely for better debugging inside Visual Studio 2008, not any other use. You are truly not permitted to not just copy but also to read with intend to use it for learning or inspiration in your open projects (if any!).

Frans Bouma (the key guy behind LLBLGen, one of the best .NET ORMs) had a very detailed take on this earlier. I think you need to read it.

Read How to Setup and Use The Source Code