dotnet interop: Is it possible to retrieve an item's "sizeconst" value dynamically?

I have the following member defined in a class:
[MarshalAs(UnmanagedType.ByValArray, SizeConst = 5)]
private char[] units;

I want the code that values the units member to know the value of
SizeConst. I know I can define the size in another member but
accessing the SizeConst would make things much cleaner for what I am
trying to do.

Thanks,
Mike

[quoted text, click to view]

Depends on which version of .NET you're using. In v1.x it was
nontrivial to do. As of 2.0 you should just have to use regular
Reflection and look for the MarshalAs attribute.


Mattias

--
Mattias Sjögren [C# MVP] mattias @ mvps.org
http://www.msjogren.net/dotnet/ | http://www.dotnetinterop.com

[quoted text, click to view]


Why? SizeConst (as hinted by the name) is a constant. You are telling the
marshaller that you will be marshalling a 5 element array. Everything
(including your initializer of units = new units[5]) must use that constant
size. If possible, I would also make the units member readonly (I can't
remember if this is possible with interop though).

For .NET code, you can use a

const int unitArraySize = 5;

and reference that value anywhere you need to know the size of the array:

[MarshalAs(UnmanagedType.ByValArray, SizeConst = unitArraySize)]
private char[] units = new units[unitArraySize];

void function
{
// I need to know the size. you can use unitArraySize, but I
personally would use units.Length.
}

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