MATLAB Builder NE (.NET Assembly) Data type question

Question

I am using MATLAB Builder NE (MATLAB's integrated .NET assembly builder), but I am having an issue with data types.

I have compiled a small, very simple, function in MATLAB and build it for .NET. I am able to call the namespace and even the function just fine. However, my function returns a value, and MATLAB defaults to returning it as an object[] data type. However, I know that the value is an integer, but I can't figure out how to cast it.

My MATLAB function looks like this:

function addValue = Myfunction(value1, value2)

addValue=value1+value2;

end

Pretty simple right?

And then in .NET I can call it as:

xClass.addValue (1, 3, 4);

where xClass is the name of the MATLAB built class but when I try:

int x = xClass.addValue (1, 3, 4);

C# errors out. Typical .NET casting (int) doesn't work. The compiler states it cannot convert object[] to int.

Does anyone have experience with the .NET builder in MATLAB that can help me with this? It is really throwing me for a loop. I have scanned through most of the MATLAB BUILDER doc (484 pages!) with zero help.

Answer 1

When I do that, I get a conversion error as well. However, I typed:

result[0] into the intermediate window and it came back with:

> {int[1, 1]}
>     [0, 0]: 7

I just can't isolate the "7" and it is driving me crazy. :-)

Answer 2

The result is Object[] because Matlab can return a vector of result parameters.

I haven't used Matlab NE for a while, so I can't remember the exact syntax, however, Matlab uses MWArray's, you'll have to examine MWArray's member to see what you have access to.

I think result[0] is a MWArray containing an int.

Answer 3

What you are seeing in the immediate window is telling you that result[0] contains a two dimensional array that is of length 1 in both dimensions. The data is in the [0,0] element because the array is 0-based.

The following cast looks ugly, but will assign 7 to x:

int x = ((int[,])result[0])[0,0]

Answer 4

I no longer have Builder NE, but if I remember correctly you can do something like:

using MathWorks.MATLAB.NET.Utility;
using MathWorks.MATLAB.NET.Arrays;

int x = ((MWNumericArray)(xClass.addValue(1, 3, 4)).ToScalarInteger();

Using IntelliSense and the class browser on the MWArray, MWCellArray, MWStructArray, and MWNumericArray types was a lot more useful than the MATLAB documentation.

Having said all that, though, I'm confused by the first parameter in your addValue call?