Vb to C# DLL library problem

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Hello.
From some time I try to solve this problem without any success.
Any help would be greatly appreciated.

I have external library DLL with needed methods to do some calculation on inputs and gives me the output (I don't have acces to code)
------------------------------------------------------
The working excel VB script to call this library is

VB

Dim Inputs() As Double
Dim Outputs() As Variant
ReDim Inputs(1 To 1, 1 To NbrInputs&)
For i& = 1 To NbrInputs&
Inputs(1, i&) = CDbl(InRange(i&).Value)
Next i&

VB

ABC.CalculateMatrix(Inputs#, Outputs)

------------------------------------------

I have great problem interfacing the library with C#
the method should be in C#
ABC.CalculateMatrix(ref System.Array, ref System.Array)
The input and output arrays do not seem to work.I've tried nearly everything

What I have tried:

C#

Double[] Inputs = new Double[4];
Object[] Outputs = new Object[1]; 
ABC.CalculateMatrix(Inputs, Outputs);

And the error i get is
System.Runtime.InteropServices.COMException'
Object variable or With block variable not set

Posted 24-Apr-18 21:41pm

Member 13797060

Updated 25-Apr-18 21:31pm

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Richard Deeming · Answer 1 · 2018-04-25T07:42:00

Quote:

ReDim Inputs(1 To 1, 1 To NbrInputs&)

That creates a two-dimensional array with a non-zero lower bound. To duplicate that in C#, you would need:

C#

Array Inputs = Array.CreateInstance(
    typeof(double), 
    new[] { 1, NbrInputs }, // lengths
    new[] { 1, 1 });        // lower bounds

for (int i = 1; i <= NbrInputs; i++)
{
    double value = Convert.ToDouble(InRange[i].Value);
    
    // NB: Can't use indexer to set the value for a non-zero lower bound:
    Inputs.SetValue(value, 1, i);
}

It's not clear from the code you've posted what needs to be passed to the Outputs parameter. You would need to check the documentation of the third-party code to see if that gives you any clues.

User 7429338 · Answer 2 · 2018-04-24T22:02:00

Solution 1

ABC.CalculateMatrix expects references:

System.Array Inputs = Array.CreateInstance(typeof(Double), 4);
System.Array Outputs = Array.CreateInstance(typeof(Object), 1);
ABC.CalculateMatrix(ref Inputs, ref Outputs);

Posted 24-Apr-18 22:02pm

User 7429338

Updated 24-Apr-18 22:10pm

v2

Comments

Member 13797060 25-Apr-18 4:03am

//After change to ABC.CalculateMatrix(ref Inputs, ref Outputs);
I get following errors:

cannot convert from 'ref double[]' to 'ref System.Array'
cannot convert from 'ref object[]' to 'ref System.Array'

[no name] 25-Apr-18 4:09am

You can use Array.CreateInstance to create arrays of the correct type in that case. I've updated my original reply with an example.

Member 13797060 25-Apr-18 4:14am

After changing to

System.Array Inputs = Array.CreateInstance(typeof(Double), 4);
System.Array Outputs = Array.CreateInstance(typeof(Object), 1);
ABC.CalculateMatrix(ref Inputs, ref Outputs);

I get following ERROR
Object variable or With block variable not set

[no name] 25-Apr-18 4:47am

That seems like a VB error thrown by ABC.CalculateMatrix, instead of a problem with the way of calling from C#. I hope someone else can help with the VB part, since I'm not experienced with that.