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The C# 5.0 beta release is now available

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I am super excited to announce that the beta release of Visual Studio version 11 (which includes the .NET CLR version 4.5, Visual Basic version 11 and C# version 5) is available for download right now. As you know if you've been following our CTP releases, in C# and VB we've greatly improved the ease of programming in an asynchronous "continuation-passing" style such that the compilers do the hard work of rearranging the code into a form amenable to asynchrony, so that you don't have to. VB also now has iterator blocks, and has surpassed C# in that VB iterator blocks can even be inside lambdas. Pretty neat.

And that's just the big stuff for C# and VB; there is an enormous amount of new stuff here in the languages, the tools and the runtime. I can't wait to see what developers do with all of these amazing features. Please, download the beta and give us feedback on what you like and what you don't like.

See the following blog posts for more details:

* Jason Zander
* C# Team
* VB Team

Comments

  • Anonymous
    February 29, 2012
    Does it include a runtime so we can use programs compiled with C# 5(and using async-await) on .net 4? Or do we still need to use the library included with the old AsyncCTP for that? The beta does not include such a library, no. We hope to be able to provide a new one some time before VS 11 ships, but are not making any promises at this time. -- Eric

  • Anonymous
    February 29, 2012
    Great to know, Congratulations, thank you!

  • Anonymous
    February 29, 2012
    Congrats!  Very exciting, I can't wait to use Async in production apps.

  • Anonymous
    February 29, 2012
    VB gets iterator lambdas while C# doesn't? I don't want to live on this planet anymore. :)

  • Anonymous
    February 29, 2012
    I thought the trend was to match CLR to C# version number? Nope. See http://stackoverflow.com/a/247623/88656 for a summary of the version number mismatches. -- Eric

  • Anonymous
    February 29, 2012
    Am I correct that the only new features in C# 5 are async/await and the new caller info attributes? Those are the big ones. We've also added improved support for using the Windows 8 runtime library from C#, and fixed the semantics of closures in foreach loops. -- Eric I was kind of hoping for more little things, like being able to speficy Enum and Delegate as generic type constraints (which should be almost free) or tuple unpacking. Sorry to disappoint. The platitudes "you can't please everyone" and "the perfect is the enemy of the good" come to mind. -- Eric

  • Anonymous
    February 29, 2012
    @Gabe I still check now and then if it is possible to set constructor arguments types in a generic constraints (eg: "where T : new(int, string)"). Besides not having that feature, that doesn't keep me unmotivated, as the new async features look really nice, and I'm sure I'll write a lot of code with them :)

  • Anonymous
    February 29, 2012
    The comment has been removed

  • Anonymous
    February 29, 2012
    Hello I have a feeling that following example will not work as expected: lock(syncRoot) {    await ReadDataFromFileAsync("data.txt"); } Am I right? Yes, this example is logcally abit wrong. But still. Imagine that "lock" statement is several levels up in the call stack.

  • Anonymous
    March 01, 2012
    when can we expect silverlight support?

  • Anonymous
    March 01, 2012
    @petka: This is forbidden by the spec. await cannot occur inside a lock block (nor a catch as well as a few other restrictions...)

  • Anonymous
    March 01, 2012
    I know this is a VS not a C# question but as they go hand in hand: are there any plans to release x64 versions of Visual Studio, or support edit-and-continue in 64-bit C# code?

  • Anonymous
    March 01, 2012
    Congrats, awaiting the new version!

  • Anonymous
    March 02, 2012
    Excellent! Therefore, in the upcoming months, we can expect posts about meta programming features for C# 6.0 ;) I cannot wait!

  • Anonymous
    March 03, 2012
    I vote for allowing writing async/await programs targeting .NET 4.0! All that's needed is for the compiler to be happy to find the necessary types (eg AsyncTaskMethodBuilder) in any assembly, rather than just looking in mscorlib. Then we can ad-lib a solution, for example using the old AsyncCtpLibrary.dll.

  • Anonymous
    March 04, 2012
    nice to know that c# and Vb will go to the next level with asynchronous programming... can't wait for the release.

  • Anonymous
    March 11, 2012
    Eric, Any plans to add something along the lines of CallerMemberType in the future? This would also help in logging and databinding scenrios quite a bit. Thanks, KShaban

  • Anonymous
    March 19, 2012
    Any chance for enum-generic constraints? ( ... where T. enum ... )

  • Anonymous
    April 19, 2012
    Great. Congrats microsoft.

  • Anonymous
    June 02, 2012
    Nice post! Thanks , for providing the new tool in the Visual studio in the .NET programming . I hope that it becomes more powerful than old .I will try it to use this tool. I send love, affection,strength to you for providing the tool in the .NET programming. <a href="ecommercesoftwarereviewss.com/">ecommerce reviews</a> Thanks for sharing the information .