Breaking Changes from V1.1 to Whidbey Beta1

The team has worked incredibly hard to ensure that every V1.1 application works great on Whidbey, but there are a handful of issues mostly related to security and correctness that we felt like we had to fix.  Kit just got this list published.  We also published the list of members that are obsoleted in Whidbey beta1.  We would love to have your feedback on how any of these impact your applications. 


For reference, other breaking change information can be found here:



Comments (10)

  1. David James says:

    Re: "The V2.0 runtime looks for and consumes the /cor command line switch on all applications."

    Is there a reason the switch had to be "/cor", or did you just choose a name?

    Could you declare certain command line switches as "reserved for future use"? E.g. make all switches starting with "/dotnet" reserved, and remove them from args[] passed to Main, so you don’t have to make future breaking changes like this one.

  2. RichB says:


    Message: Use OptimizedDoubleBuffer instead

    What is it about OptimizedDoubleBuffer which is not a black-box change from DoubleBuffer? Is it really such a major change, or can’t we just stick with the old ControlStyles enumeration value and just get the new behaviour?

    (I remember when .Net didn’t even have the DoubleBuffer option and I had to use sample code from Chris Anderson… ah, memories 🙂

  3. Opening the doublebuffer black-box will be of great benefit for us.

    In particular, we’d like to have access to the internal Bitmap image class used as back buffer.

  4. JFo says:

    Re: OptimizedDoubleBuffer

    I believe it’s still safe to use DoubleBuffer – existing code should not be affected.

    Re: Opening the black box

    Check out the BufferedGraphics class…

  5. Alberto Falossi says:

    FYI, one of the guys of my team at the dotnet2themax site wrote an online

    .net object browser ( which lets you see

    all the types that have been added or changed in Whidbey. The browser can

    also list all the types that are marked with a given attribute (or that

    implement a given interface or derive from a given base class), so you can

    get easily list all the items marked as obsolete at this URL:


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