Re: Structures not behaving as value types

Can you put up your code?

On Mon, Feb 25, 2008 at 10:44 AM, Richard Kucia <[email protected]> wrote:
> Well, in fact it does. The mask structure contains one array of N 32-bit integers to hold the bits. Each time any function or property of the mask is invoked, that code tests the array to see if it is (nothing), and Redim's it.
>
>  So that explains it. The formula mentioned below takes the most recently used mask structure and shifts it left 1 bit. So each request for another mask is obviously getting the same object reference, and when the bit-shift occurs, it effectively occurs in every mask structure, since they are all referencing the same array.
>
>  So what is the correct way to handle this? I want each structure to have its own independent array of N 32-bit integers.
>
>  Rick
>  -------------- Original message from Matthew Wills <[email protected]>: --------------
>
>
>
>  > Richard,
>  >
>  > Show us the code for strFieldMask. I would bet you are using some reference
>  > types in it.
>  >
>  > Seeya
>  > Matthew Wills | Solution Designer | Adviser Tools and Services | Financial
>  > Planning and Third Party | NAB Technology
>  >
>  > Phone: 02 9376 4029 | Mobile: 0435 002 520 | Email:
>  > [email protected]
>  >
>  >
>  >
>  >
>  > Richard Kucia
>  >
>
>
> > To
>  > [email protected]
>  > cc
>  >
>  > Subject
>  > [DOTNET-CLR] Structures not
>  > behaving as value types
>  >
>  > I have a VB.Net declaration of a structure strFieldMask. The intended
>  > purpose is to store a bunch of bits, like a bit vector. The structure also
>  > has operator declarations for =, <>, And, Or, Not and <<, plus some other
>  > methods for bit manipulation.
>  >
>  > The problem is that variables of type strFieldMask seem to behave as
>  > though there was a singleton strFieldMask and all instances shared it.
>  >
>  > Consider this:
>  >
>  > Dim Mask1 as strFieldMask
>  > Dim Mask2 as strFieldMask
>  >
>  > Mask1 = (formula for computing the next unused mask value)
>  > Debug.WriteLine(Mask1.ToString))
>  > Mask2 = (same formula)
>  > Debug.WriteLine(Mask1.ToString)) ' Yes, Mask1, not Mask2
>  >
>  > The result from the first WriteLine might be "0x10" and the result from
>  > the second WriteLine might be "0x20".
>  >
>  > I've successfully used structures before, but this is the first time I've
>  > tried overloading the operators. Has that caused the behavior I'm seeing?
>  >
>  > Thanks.
>  >
>  >
>  >
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