asked on

How to declare an Array to send as ref

There is a DLL I use that had a Method that looks like this:

AskJobPages(ref Array Pages)

So I should declare an Array and send it as a ref. The method will fill the array with pagenumbers (int).

I tried this:

            Array pages = new int[999];
            clarity.AskJobPages(ref pages);

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But this is not the way. I get the errormessage:

Value does not fall within the expected range.

on the second line.

Any suggestions?

kaufmed

Yes, that is the correct way to pass variables so they will be directly modified within the called method (since the method is defined with a ref parameter). Is it possible to see the definition of AskJobPages?

omroepbrabant

ASKER

No, I don't have the source and the documentation is not program language speciffic.

I wonder if the message "Value does not fall within the expected range" indicates that the array is of the wrong length.
I don't know the length of the resulting array.

kaufmed

I wonder if the message "Value does not fall within the expected range" indicates that the array is of the wrong length.

Which is what I thought as well. I wondered if the target function was expecting a smaller array than 999.

omroepbrabant

ASKER

I've tried a smaler array,
100, 10, even 1.

kaufmed

Out of curiosity, what is the type of the exception being raised?

ASKER CERTIFIED SOLUTION

fromer

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kaufmed

@fromer

"ref" parameters imply that the variable is initialized prior to the function call containing the "ref" param. "out" params are ones that can be null before being passed to a function that accepts such a parameter.

fromer

Yes you are right...
What is the purpose of passing a Reference Type as ref parameter?...function implies that, if the size of the array is not enough, i may ReConstruct it (ReAllocate, ReCreate, Grow)....
i don't think that, the exception occurs due to the size of the Array...It comes from the internal structure of the method...

fromer

The purpose of my suggestion was to learn if the method ReConstructs (ReAllocate, ReCreate, Grow) the array parameter..if you we send null as parameter, and the method does not reconstructs it, then the exception should turn to be an Access Violation exception...

omroepbrabant

ASKER

Passing an empty Array worked like fromer sugested, it fills the array for me... Thank you!