Today, we are happy to announce the availability of Microsoft .NET Framework 4.5 and Visual Studio 2012. You can develop apps that will take advantage of all the great features that we have added, including new features in Windows 8. We are also announcing the availability of the .NET Framework 4.5 reference source code.

You can read more about the Visual Studio 2012 release on Jason Zander’s blog and Soma’s blog. Please visit the Visual Studio 2012 downloads page to install both products.

Improvements in the .NET Framework 4.5

We have made many improvements in the .NET Framework 4.5. Many of these advances help you write better apps with less effort, while others help you target particular Microsoft platforms. In either case, you’ll find the new features useful and relevant for the apps that you write today.

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Releasing the source code for the .NET Framework 4.5 libraries

In addition to releasing the .NET Framework 4.5, we are pleased to announce that we are also releasing the source code for the .NET Framework libraries. While you may enjoy reading the many interesting algorithms in our product, we release the .NET Framework source primarily to improve your debugging experience. Having access to all the managed source for the code running in your process provides you with a lot more information about what your app is actually doing.

If you are new to developing with the .NET Framework, you may not know that we have released the source and rich symbols in past versions. We know that many developers rely on our source code to efficiently get to the root cause of functional and performance problems in their apps. As a result, we provide the source code concurrently with the release of .NET Framework 4.5.

This release includes the following:

• Downloadable source code
• Source available on-demand, deployed to the Microsoft Reference Source Server
• Rich symbols (PDB files) for .NET Framework 4.5 source, deployed to the Microsoft Reference Source Server

We’ll now look at how you can use the source code and symbols.

Debugging with .NET Framework library reference source

You may be wondering what debugging with .NET Framework reference source looks like. In the example below, you will see a tool of mine calling the public Console.WriteLine method. From there, the WriteLine method calls several private managed APIs, and eventually ends with one or more platform invoke calls. You can see each of these calls in the Call Stack window. You can look at each call frame, both in terms of the source for that frame, and any locals that are available. That’s pretty useful!

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Who needs Reflector for spelunking the .Net Framework source when you've got... well... the source! :)