MATLAB: How to use a Collection.ArrayList in the C# application and pass it to the MATLAB .NET component

arraylistbuildercforMATLABMATLAB Builder for COMnet

I want to create an Collections.ArrayList in C# and pass it to a .NET component created with MATLAB Builder for .NET.

Best Answer

You can use the ICollection.CopyTo method to make a shallow copy of the elements of the collection to a standard C# array. You can then cast this array to a MATLAB data type. Here is a simple exmple:

MATLAB code:

function ConsolePrinter(A)
disp(A)

C#-code:

using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;
using MathWorks.MATLAB.NET.Arrays;
using ConsolePrinter;
namespace ConsoleApplication1
{
      class Program
      {
          static void Main(string[] args)
          {
              //Instanciate the MATLAB component
              ConsolePrinterclass Pr = new ConsolePrinterclass();            
              //Initialize and populate a Collections.ArrayList
                  ArrayList list1 = new ArrayList(5);
                  list1.Add("Jody");
                  list1.Add("Red");
                  list1.Add("John");
                  list1.Add("Xiaoyu");
                  list1.Add("Black");
              //Create shallow copy of the ArrayList alements to an array
                  string[] array1 = new string[5];
                  list1.CopyTo(array1, 0);
              //print container element to screen
                  foreach (string i in array1)
                  {
                      Console.WriteLine("Element as native C# array:\n" + "\t" + i);
                      Console.WriteLine("Element as MathWorks type from MCR:");
                      Pr.ConsolePrinter(new MWCellArray(i));
                  }
              //wait for user to exit
                  Console.ReadLine();               
              }
          }
      }

You may need to invoke IDisposible.Dispose method to garbage collect the collection.

This method will work for any of the System.Collections objects i.e. deque, queue, stack...

Related Solutions

MATLAB: How to pass an array of strings from C# to MATLAB using MATLAB Builder NE 3.0.2 (R2009b)

It is possible to create a string array in C# and pass it to an MWCharArray like below:

String[] input = new String[2] {"This", "is"};

MWCharArray inputStr = new MWCharArray(input);

But unfortunately, MWCharArray sends the array of strings to MATLAB as a column vector but not as a row vector. Thus it is not very useful when we send array of strings in the above way.

So the best way to send array of strings from C# to MATLAB is by creating an MWCellArray. Please see below for a complete example on how to pass array of strings from C# to MATLAB:

Here is simple MATLAB code which takes input as a cell array and concatenates the contents of cell array with other strings:

function result = concatStringArrays(input)
strVar = ['a', 'concatenated', 'string'];
result = [input{1}, input{2}, strVar];
end

Please note that Matlab array starts at index 1 instead of 0 unlike in C#

After creating the .NET component from the above MATLAB code, the component can be used in the C# .NET application like below:

using System;
using System.Collections.Generic;
using System.Text;
using MathWorks.MATLAB.NET.Utility;
using MathWorks.MATLAB.NET.Arrays;
using stringArray;
namespace StringArr
{
      class Program
      {
          static void Main(string[] args)
          {
              MWCellArray inputString = null;
              MWCharArray resultString = null;
              try
              {
                  StringArray demo = new StringArray();
                  inputString = new MWCellArray(2);
                  inputString[1] = new MWCharArray("This");
                  inputString[2] = new MWCharArray("is");
                  Console.WriteLine("String input converted to pass to MATLAB .NET component is\n{0}", inputString);
                  resultString = (MWCharArray)demo.concatStringArrays(inputString);
                  Console.WriteLine("resulting string from MATLAB function is {0}", resultString);
                   Console.ReadKey();
              }
              catch (Exception exception)
              {
                  Console.WriteLine("Error: {0}", exception);
                  Console.ReadKey();
              }
          }
      }
}

MATLAB: How to copy data to a new string variable in a C-MEX file

Use the mxArray* returned by the mxCreateString function to copy data to a new mxArray* as follows:

 #include "mex.h"
 void mexFunction( int nlhs, mxArray *plhs[],
                   int nrhs, const mxArray *prhs[] )
 {
 mxArray *origString, *userString;
 int arrayLen;
 /* Initialize */
 origString = mxCreateString("This is the primitive string");
 /* Copy values to new string */
 userString = origString;
 /* Determine array length */
 arrayLen = mxGetNumberOfElements(origString);
 printf("The array length is: %d \n", arrayLen);
 /* Remaining code is just for testing */
 plhs[0] = userString;
 return;
 }

To test the above mexFunction after building to a MEX file, for example mexFunction.mexw32, invoke:

y = mexFunction

Best Answer

Related Solutions

MATLAB: How to pass an array of strings from C# to MATLAB using MATLAB Builder NE 3.0.2 (R2009b)

MATLAB: How to copy data to a new string variable in a C-MEX file

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