What’s New in the BCL in the .NET Framework 4.5 [Immo]

If I were a Microsoft executive I would probably introduce this post with “I’m super excited to announce…” but I’m not. I’m just an engineer. Well, an incredibly proud engineer nonetheless. In any case, I’m proudly spreading the news: the Release Candidate of Visual Studio 2012 and the .NET Framework 4.5 are now available. Uh, and by the way, Windows also shipped the Release Preview of Windows 8 which means you can install them together!

If you want to learn more about the BCL related improvements we did in this release, I recommend reading our MSDN Magazine article What’s New in the .NET 4.5 Base Class Library. If you want to learn more about .NET wide features you should take a look at our .NET Blog, too.

You can also get a sneak peek into the backstage area of the BCL by watching our Channel 9 interview. You can meet our team and learn more about the thinking process that went into the features we did. Specific topics we covered: Async across the framework, read-only collections, ETW APIs, Reflection Context, MEF, and WeakReference<T>.

We hold a reasonably high quality bar for our pre-release products – in fact, both Visual Studio 11 Beta and the .NET Framework 4.5 Beta already came with a go-live license, which means we supported application design, development, test, and deployment in test and production environments. Of course, the same applies to the Release Candidate as well.

However, since this still is pre-release software chances are you will find some rough corners. Please let us know about those, so we get a chance to address them.

Have fun!

Comments (5)

  1. Andrew says:

    Great work all. Many of the BCL types have been given Async methods. However, many types, such as TcpClient, don't seem to respect the CancellationToken that these methods are passed. This means you can end up with tasks that simply never end – and can't be cancelled. Please can you let us know what your guidance is for dealing with these cases.

    thanks, Andrew

  2. Andrew says:

    Let me rephrase that: the Async methods of TcpClient's underlying NetworkStream don't seem the respect the CancellationToken…

  3. BCLTeam says:

    Hi Andrew,

    thanks for reporting this issue. After talking to the owners of the networking APIs it turns out this is a known limitation of the existing networking APIs. They already file a bug for this and will consider it for the next release.


    Immo Landwerth

  4. Nodir says:

    I think you meant "sneak peek", not "sneak peak"

  5. Nodir: Good catch! 🙂

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