problem with using a " dll created in matlab" in c#

hi
I Need some help with the calling of a matlab compiled DLL (C# under
deploytool). The matlab function is a simple function THAT takes two double and return a
third...

i add necessary references to my c# project ...

and its my code :

Sum.Class1 a = new Sum.Class1();
           MathWorks.MATLAB.NET.Arrays.MWArray[,] s=new MWArray[1,3];

           a.sumab(2, 5, s);

             listBox1 .Items.Add(s);

the method (sumab) return void and i dont know how can get my output ...
im very amazing

if i just write a.sumab(2,5);
it gives me an error:

"

... MWMCR::EvaluateFunction error ...
Error using ==> sumab
Too many output arguments..

"

please help me friends
tnx a lot

Tags: C#, MatLab