3

Hi I am trying to access a c++ array of struct from c#. The struct itself also contains an array of strings and a String. The details are below. It's not working.. does not crash but does not transfer the data across (e.g. get nulls in the array, and random number in numberOfRows integer of struct/class). See my comments at the end of the code listing. Any suggestions?

c++ cppClassLib.cpp

// This is the main DLL file.



  #include "stdafx.h"
    #include <Objbase.h>

    #include "cppClassLib.h"

    #include <string.h>
    //#include <malloc.h>

    namespace cppClassLib {

    /*
    http://msdn.microsoft.com/en-us/magazine/cc164123.aspx
    http://stackoverflow.com/questions/9093292/use-a-c-library-from-c-sharp-code
    http://stackoverflow.com/questions/5671658/what-does-invalid-managed-unmanaged-type-combination-mean
    http://stackoverflow.com/questions/2338146/returning-pointers-from-unmanaged-to-managed-code
    CoTaskMemAlloc http://msdn.microsoft.com/en-us/library/windows/desktop/ms692727%28v=vs.85%29.aspx
    */

    char *createStr(char *input)
    {
        int len = strlen(input)+1;

        // can't use malloc because it needs to
        //  be accessible from another process.
        // can't use CoTaskMemAlloc because get an
        // error when trying to link, not found.
        //char *newStr = (char *)CoTaskMemAlloc(len);
        //char *newStr = (char *)malloc(len);

        char *newStr = (char *)GlobalAlloc(GPTR,len);
        //char* newStr = new char[len];
        strcpy_s(newStr, len, input);
        return newStr;
    }

    int Class1::getMatrixNumberOfRowsInColumnZero(int maxColumns, Class1::columnT *matrix)
    {
        if (maxColumns < 1) {
            return 0;
        }
        return matrix[0].numberOfRows;
    }

    int Class1::getMatrix(int maxColumns, Class1::columnT *matrix)
    {
        if (maxColumns < 2) {
            return 0;
        }
        int numberOfColumns = 2;

        //Class1::columnT *column0 = (Class1::columnT *)GlobalAlloc(GPTR,sizeof(Class1::columnT));
        Class1::columnT *column0 = &(matrix[0]);
        column0->columnName = createStr("Col0");
        int numRows = 2;
        column0->numberOfRows = numRows;
        char **rows = (char **)GlobalAlloc(GPTR,sizeof(char *)*numRows);
        rows[0] = createStr("C0R0");
        rows[1] = createStr("C0R1");
        column0->rows = rows;

        Class1::columnT *column1 = &(matrix[1]);
        //Class1::columnT *column1 = (Class1::columnT *)GlobalAlloc(GPTR,sizeof(Class1::columnT));
        column1->columnName = createStr("Col1");
        numRows = 2;
        column1->numberOfRows = numRows;
        rows = (char **)GlobalAlloc(GPTR,sizeof(char *)*numRows);
        rows[0] = createStr("C1R0");
        rows[1] = createStr("C1R1");
        column1->rows = rows;

        //matrix[0]=column0;
        //matrix[1]=column1;
        //(matrix[0])->columnName = createStr("Test0");

        return numberOfColumns; // 2
    }

    int Class1::getInt(void)
    {
        return 1234;
    }

    char* Class1::getHi(void)
    {
        //char *result = createStr("Hello");
        //return result;
        //return createStr("hello");
        return createStr("hello");
    }

    char** Class1::getHeaderList(void)
    {
        char** list;
        list = (char **)GlobalAlloc(GPTR,sizeof(char *)*2);
        list[0]=createStr("test1");
        list[1]="test2";
        return list;
    }

    int Class1::getHeaderListTwo(int maxsize, char ***result)
    {
        char** list;
        int len = 2;
        if (maxsize < len) {
            return NULL;
        }
        list = (char **)GlobalAlloc(GPTR,sizeof(char *)*maxsize);
        list[0]=createStr("test01");
        list[1]="test02";
        for (int i=2; i<maxsize; ++i) {
            list[i]="";
        }
        *result = list;
        return len;
    }

    char* Class1::getHi2(void)
    {
        return "Hi";
    }

    char* Class1::getHi3(void)
    {
        return "Hi!";
    }

    void Class1::getData(int *totalColumns,
                    char** headers[2],
                    char** items[2][3])
    {
        *totalColumns = 2;
        *headers[0]=createStr("Testing");
        *headers[1]=createStr("Pets");
        *items[0][0]=createStr("test1");
        *items[0][1]=createStr("test2");
        *items[0][2]=createStr("test3");
        *items[1][0]=createStr("Cats");
        *items[1][1]=createStr("Dogs");
        *items[1][2]=createStr("Fish");
    }

}

c++ cppClassLib.h

    // cppClassLib.h

    #pragma once

    using namespace System;

    #define DllExport   __declspec( dllexport )

    // http://msdn.microsoft.com/en-us/library/3y1sfaz2.aspx

    namespace cppClassLib {

    public class Class1 {
        public:
            struct columnT {  
                int numberOfRows;
                char **rows;
                char *columnName;
            };
            static DllExport int getMatrix(int maxColumns, columnT *matrix);
            static DllExport int getMatrixNumberOfRowsInColumnZero(int maxColumns, columnT *matrix);
            static DllExport void getData(int *totalColumns,
                    char** headers[2],
                    char** items[2][3]);
            static DllExport char *getHi(void);
            static DllExport char *getHi2(void);
            static DllExport char *getHi3(void);
            static DllExport int getInt(void);
            static DllExport char** getHeaderList(void);
            static DllExport int getHeaderListTwo(int maxsize, char ***result);
    };
}

c# Form1.cs

  using System;
    using System.Collections.Generic;
    using System.ComponentModel;
    using System.Data;
    using System.Drawing;
    using System.Linq;
    using System.Text;
    using System.Windows.Forms;

    using System.Runtime.InteropServices;

    /*

    http://msdn.microsoft.com/en-us/library/aa288468%28v=vs.71%29.aspx
    http://ondotnet.com/pub/a/dotnet/2002/03/18/customcontrols.html?page=2
    http://www.codeproject.com/Articles/2995/The-Complete-Guide-to-C-Strings-Part-I-Win32-Chara
    http://msdn.microsoft.com/en-us/library/z6cfh6e6.aspx

    */

    namespace listViewFromC
    {
    public partial class Form1 : Form
    {
        /*
        [DllImport("cppClassLib.dll",
        CallingConvention = CallingConvention.Cdecl,
        EntryPoint = "?getInt@Class1@cppClassLib@@QAEHXZ")]
            public static extern int getInt();
        */

        // get EntryPoint using
        // "DLL Export Viewer" software

        [DllImport("cppClassLib.dll",
        CallingConvention = CallingConvention.Cdecl,
        EntryPoint = "?getHi2@Class1@cppClassLib@@SAPADXZ")]
            public static extern String getHi2();

        [DllImport("cppClassLib.dll",
        CallingConvention = CallingConvention.Cdecl,
        EntryPoint = "?getHi@Class1@cppClassLib@@SAPADXZ")]
        [return: MarshalAs(UnmanagedType.LPStr)]  
        public static extern string getHi();

        [DllImport("cppClassLib.dll",
        CallingConvention = CallingConvention.Cdecl,
        EntryPoint = "?getHeaderList@Class1@cppClassLib@@SAPAPADXZ")]
        [return: MarshalAs(UnmanagedType.LPArray, 
            ArraySubType=UnmanagedType.LPStr, SizeConst=2)]
        public static extern String[] getHeaderList();

        [DllImport("cppClassLib.dll",
        CallingConvention = CallingConvention.Cdecl,
        EntryPoint = "?getHeaderListTwo@Class1@cppClassLib@@SAHHPAPAPAD@Z")]
        public static extern int getHeaderListTwo(int maxsize,
            [MarshalAs(UnmanagedType.LPArray,
            ArraySubType = UnmanagedType.LPStr, SizeParamIndex = 0)]
            ref String[] result
            );

        [StructLayout(LayoutKind.Sequential)]  
        public class columnType
        {
            public int numberOfRows;
            [MarshalAs(UnmanagedType.LPArray,
            ArraySubType = UnmanagedType.LPStr)]
            public String[] rows;
            [MarshalAs(UnmanagedType.LPStr)]
            public String columnName;
        }  

        [DllImport("cppClassLib.dll",
        CallingConvention = CallingConvention.Cdecl,
        EntryPoint = "?getMatrix@Class1@cppClassLib@@SAHHPAUcolumnT@12@@Z")]
        public static extern int getMatrix(int maxColumns,
            [MarshalAs(UnmanagedType.LPArray,
            ArraySubType = UnmanagedType.Struct, SizeParamIndex = 0)]
            columnType[] matrix);

        [DllImport("cppClassLib.dll",
        CallingConvention = CallingConvention.Cdecl,
        EntryPoint = "?getMatrixNumberOfRowsInColumnZero@Class1@cppClassLib@@SAHHPAUcolumnT@12@@Z")]
        public static extern int getMatrixNumberOfRowsInColumnZero(int maxColumns,
            [MarshalAs(UnmanagedType.LPArray,
            ArraySubType = UnmanagedType.Struct, SizeParamIndex = 0)]
            columnType[] matrix);

        /*
        [DllImport("kernel32.dll")]
        static extern IntPtr GlobalAlloc(uint uFlags, uint dwBytes);

        const uint GMEM_FIXED = 0x0000;
        const uint GMEM_ZEROINIT = 0x0040;
        const uint GPTR = GMEM_FIXED | GMEM_ZEROINIT;
        */

        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            //label1.Text = getInt().ToString();
            label1.Text = getHi2();
            listView1.Items.Clear();
            listView1.Items.Add(label1.Text);
            //listView1.
        }

        private void button2_Click(object sender, EventArgs e)
        {
            label1.Text = getHi();
        }

        private void button3_Click(object sender, EventArgs e)
        {
            const int maxsize = 2;
            String[] headerList = new String[maxsize];
            int len = getHeaderListTwo(maxsize, ref headerList);
            MessageBox.Show("Got length " + headerList.Length+" ("+len+")");
            label1.Text="";
            for (int i = 0; i < headerList.Length; ++i)
            {
                if (headerList[i].Length>0)
                {
                    label1.Text += headerList[i].ToString() + " // ";
                }
                else
                {
                    label1.Text += " // ";
                }
            }
        }

        private void button4_Click(object sender, EventArgs e)
        {
            int maxColumns=5;
            int numberOfColumns = 0;
            columnType[] matrix = new columnType[maxColumns];
            for (int i = 0; i < maxColumns; ++i)
            {
                matrix[i] = new columnType();
            }
            matrix[0].numberOfRows = 1; // pick something just to see if we can get it back
            //uint sz = (uint)maxColumns*4;
            //IntPtr matrixIP = GlobalAlloc(GPTR, sz);
            //columnType[] matrix = matrixIP;

            //IntPtr pointerArr = Marshal.AllocHGlobal(maxColumns*4);

            //numberOfColumns = getMatrix(maxColumns, matrix);
            label1.Text = getMatrixNumberOfRowsInColumnZero(maxColumns,matrix).ToString();

            //label1.Text = matrix[0].columnName;
        }
    }
}

button1, button2 and button3 click events work fine so it shows that some of the c++ marshalling to c# is working. button4_click doesn't work.

label1.Text should return 1 since it's just returning matrix[0].numberOfRows but in fact it returns some huge number.

Also the getMatrix call if uncommented, also doesn't work, it does run without crash but then all the elements of the array are empty (not filled with the data that getMatrix is supposed to fill them with).

Improve this question
17
  • 1
    You forgot "Pack = 4" on the StructLayout. That might be it.. Commented Jul 15, 2012 at 7:01
  • Hi I changed [StructLayout(LayoutKind.Sequential)] to [StructLayout(LayoutKind.Sequential, Pack=4)] to make sure that it store the variables every 4 bytes. However I'm still getting random numbers in the label when I run it (should be giving me 1 if it was working). Thanks for the tip though that might be the first step in the solution, though I'm not sure what's next. Commented Jul 15, 2012 at 7:31
  • (a guess) Try using StdCall instead? (add __stdcall declaration to C++ and use CallingConversion.StdCall) Commented Jul 15, 2012 at 7:34
  • @Jevan have you tried stepping though the code? Commented Jul 15, 2012 at 7:34
  • I read you should be using thiscall instead. Struts are "sequential, 4;int* vtable,data" and you call like (struct*, vars) Commented Jul 15, 2012 at 7:36

1 Answer 1

Reset to default
1

Here is my solution. The only quirk with this solution is the need for fixed length arrays in the struct, which I would have preferred a variable length array but it wouldn't accept a Marshall of LPArray. Maybe it's not possible.

The main problem I had was that I had declared it as a class instead of a struct. The other issue was the array in the struct was an LPArray unmanaged marshall type, to try and have a variable length array but that didn't work since it needed to be a ByValArray (or SafeArray) for it to work.

cppClassLib.h

// cppClassLib.h

#pragma once

using namespace System;

#define DllExport   __declspec( dllexport )

// http://msdn.microsoft.com/en-us/library/3y1sfaz2.aspx

#define maxRowsCpp 100

namespace cppClassLib {

public class Class1 {
    public:
        struct columnT {  
            int numberOfRows;
            char *rows[maxRowsCpp];
            char *columnName;
        };
        struct columnT2 {  
            int numberOfRows;
        };
        static DllExport int __thiscall getMatrix(int maxColumns, int maxRows, columnT *matrix[]);
        static DllExport int __thiscall getMatrixNumberOfRowsInColumnZero(int maxColumns, columnT matrix[]);
        static DllExport int __thiscall getMatrixNumberOfRowsInColumnZero2(int maxColumns, columnT2 matrix[]);
        static DllExport void getData(int *totalColumns,
                char** headers[2],
                char** items[2][3]);
        static DllExport char *getHi(void);
        static DllExport char *getHi2(void);
        static DllExport char *getHi3(void);
        static DllExport int getInt(void);
        static DllExport char** getHeaderList(void);
        static DllExport int getHeaderListTwo(int maxsize, char ***result);
};

}

cppClassLib.cpp

// This is the main DLL file.

#include "stdafx.h"
#include <Objbase.h>

#include "cppClassLib.h"

#include <string.h>
//#include <malloc.h>

namespace cppClassLib {

/*
http://msdn.microsoft.com/en-us/magazine/cc164123.aspx
http://stackoverflow.com/questions/9093292/use-a-c-library-from-c-sharp-code
http://stackoverflow.com/questions/5671658/what-does-invalid-managed-unmanaged-type-combination-mean
http://stackoverflow.com/questions/2338146/returning-pointers-from-unmanaged-to-managed-code
CoTaskMemAlloc http://msdn.microsoft.com/en-us/library/windows/desktop/ms692727%28v=vs.85%29.aspx
*/

char *createStr(char *input)
{
    int len = strlen(input)+1;

    // can't use malloc because it needs to
    //  be accessible from another process.
    // can't use CoTaskMemAlloc because get an
    // error when trying to link, not found.
    //char *newStr = (char *)CoTaskMemAlloc(len);
    //char *newStr = (char *)malloc(len);

    char *newStr = (char *)GlobalAlloc(GPTR,len);
    //char* newStr = new char[len];
    strcpy_s(newStr, len, input);
    return newStr;
}

int Class1::getMatrixNumberOfRowsInColumnZero(int maxColumns, Class1::columnT matrix[])
{
    if (maxColumns < 1) {
        return 0;
    }
    return (matrix[0]).numberOfRows;
}

int Class1::getMatrixNumberOfRowsInColumnZero2(int maxColumns, Class1::columnT2 matrix[])
{
    if (maxColumns < 1) {
        return 0;
    }
    return (matrix[0]).numberOfRows;
}

int Class1::getMatrix(int maxColumns, int maxRows, Class1::columnT *matrix[])
{
    // require at least able to have 2 rows and 2 columns
    if ((maxColumns < 2) || (maxRows < 2)) {
        return 0;
    }
    int numberOfColumns = 2;
    int numberOfRows = 2;
    //return matrix[0].columnName[0];

    //Class1::columnT *column0 = (Class1::columnT *)GlobalAlloc(GPTR,sizeof(Class1::columnT));
    Class1::columnT *column0 = &(*matrix[0]);
    column0->columnName = createStr("Col0");
    column0->numberOfRows = numberOfRows;
    //char **rows = (char **)GlobalAlloc(GPTR,sizeof(char *)*numRows);
    column0->rows[0] = createStr("C0R0");
    column0->rows[1] = createStr("C0R1");

    Class1::columnT *column1 = &(*matrix[1]);
    //Class1::columnT *column1 = (Class1::columnT *)GlobalAlloc(GPTR,sizeof(Class1::columnT));
    column1->columnName = createStr("Col1");
    column1->numberOfRows = numberOfRows;
    //rows = (char **)GlobalAlloc(GPTR,sizeof(char *)*numRows);
    column0->rows[0] = createStr("C1R0");
    column0->rows[1] = createStr("C1R1");

    return numberOfColumns;
}

int Class1::getInt(void)
{
    return 1234;
}

char* Class1::getHi(void)
{
    //char *result = createStr("Hello");
    //return result;
    //return createStr("hello");
    return createStr("hello");
}

char** Class1::getHeaderList(void)
{
    char** list;
    list = (char **)GlobalAlloc(GPTR,sizeof(char *)*2);
    list[0]=createStr("test1");
    list[1]="test2";
    return list;
}

int Class1::getHeaderListTwo(int maxsize, char ***result)
{
    char** list;
    int len = 2;
    if (maxsize < len) {
        return NULL;
    }
    list = (char **)GlobalAlloc(GPTR,sizeof(char *)*maxsize);
    list[0]=createStr("test01");
    list[1]="test02";
    for (int i=2; i<maxsize; ++i) {
        list[i]="";
    }
    *result = list;
    return len;
}

char* Class1::getHi2(void)
{
    return "Hi";
}

char* Class1::getHi3(void)
{
    return "Hi!";
}

void Class1::getData(int *totalColumns,
                char** headers[2],
                char** items[2][3])
{
    *totalColumns = 2;
    *headers[0]=createStr("Testing");
    *headers[1]=createStr("Pets");
    *items[0][0]=createStr("test1");
    *items[0][1]=createStr("test2");
    *items[0][2]=createStr("test3");
    *items[1][0]=createStr("Cats");
    *items[1][1]=createStr("Dogs");
    *items[1][2]=createStr("Fish");
}

}

c# Form1.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

using System.Runtime.InteropServices;

/*

http://msdn.microsoft.com/en-us/library/aa288468%28v=vs.71%29.aspx
http://ondotnet.com/pub/a/dotnet/2002/03/18/customcontrols.html?page=2
http://www.codeproject.com/Articles/2995/The-Complete-Guide-to-C-Strings-Part-I-Win32-Chara
http://msdn.microsoft.com/en-us/library/z6cfh6e6.aspx

 */

namespace listViewFromC
{
public partial class Form1 : Form
{
    const int maxRows = 100;
    /*
    [DllImport("cppClassLib.dll",
    CallingConvention = CallingConvention.Cdecl,
    EntryPoint = "?getInt@Class1@cppClassLib@@QAEHXZ")]
        public static extern int getInt();
    */

    // get EntryPoint using
    // "DLL Export Viewer" software

    [DllImport("cppClassLib.dll",
    CallingConvention = CallingConvention.Cdecl,
    EntryPoint = "?getHi2@Class1@cppClassLib@@SAPADXZ")]
        public static extern String getHi2();

    [DllImport("cppClassLib.dll",
    CallingConvention = CallingConvention.Cdecl,
    EntryPoint = "?getHi@Class1@cppClassLib@@SAPADXZ")]
    [return: MarshalAs(UnmanagedType.LPStr)]  
    public static extern string getHi();

    [DllImport("cppClassLib.dll",
    CallingConvention = CallingConvention.Cdecl,
    EntryPoint = "?getHeaderList@Class1@cppClassLib@@SAPAPADXZ")]
    [return: MarshalAs(UnmanagedType.LPArray, 
        ArraySubType=UnmanagedType.LPStr, SizeConst=2)]
    public static extern String[] getHeaderList();

    [DllImport("cppClassLib.dll",
    CallingConvention = CallingConvention.Cdecl,
    EntryPoint = "?getHeaderListTwo@Class1@cppClassLib@@SAHHPAPAPAD@Z")]
    public static extern int getHeaderListTwo(int maxsize,
        [MarshalAs(UnmanagedType.LPArray,
        ArraySubType = UnmanagedType.LPStr, SizeParamIndex = 0)]
        ref String[] result
        );

    [StructLayout(LayoutKind.Sequential, Pack = 4)]
    public struct columnType
    {
        public int numberOfRows;
        // note: can't marshal rows field as LPArray must be ByValArray or SafeArray
        // for maximum of maxRows rows
        [MarshalAs(UnmanagedType.ByValArray,
        ArraySubType = UnmanagedType.LPStr,
        SizeConst=maxRows)]
        public String[] rows;
        [MarshalAs(UnmanagedType.LPStr)]
        public String columnName;
    }

    [StructLayout(LayoutKind.Sequential)]
    public struct columnType2
    {
        public int numberOfRows;
    }

    [DllImport("cppClassLib.dll",
    CallingConvention = CallingConvention.ThisCall,
    EntryPoint = "?getMatrix@Class1@cppClassLib@@SEHHHQAPAUcolumnT@12@@Z")]
    public static extern int getMatrix(int maxColumns,
        int maxRows,
        [MarshalAs(UnmanagedType.LPArray,
        ArraySubType = UnmanagedType.Struct, SizeParamIndex = 0)]
        ref columnType[] matrix);

    [DllImport("cppClassLib.dll",
    CallingConvention = CallingConvention.ThisCall,
    EntryPoint = "?getMatrixNumberOfRowsInColumnZero@Class1@cppClassLib@@SEHHQAUcolumnT@12@@Z")]
    public static extern int getMatrixNumberOfRowsInColumnZero(int maxColumns,
        [MarshalAs(UnmanagedType.LPArray,
        ArraySubType = UnmanagedType.Struct, 
        SizeParamIndex = 0)]
        columnType[] matrix);

    [DllImport("cppClassLib.dll",
    CallingConvention = CallingConvention.ThisCall,
    EntryPoint = "?getMatrixNumberOfRowsInColumnZero2@Class1@cppClassLib@@SEHHQAUcolumnT2@12@@Z")]
    public static extern int getMatrixNumberOfRowsInColumnZero2(int maxColumns,
        [MarshalAs(UnmanagedType.LPArray,
        SizeParamIndex = 0,
        ArraySubType = UnmanagedType.Struct)]
        columnType2[] matrix);

    /*
    [DllImport("kernel32.dll")]
    static extern IntPtr GlobalAlloc(uint uFlags, uint dwBytes);

    const uint GMEM_FIXED = 0x0000;
    const uint GMEM_ZEROINIT = 0x0040;
    const uint GPTR = GMEM_FIXED | GMEM_ZEROINIT;
    */

    public Form1()
    {
        InitializeComponent();
    }

    private void button1_Click(object sender, EventArgs e)
    {
        //label1.Text = getInt().ToString();
        label1.Text = getHi2();
        listView1.Items.Clear();
        listView1.Items.Add(label1.Text);
        //listView1.
    }

    private void button2_Click(object sender, EventArgs e)
    {
        label1.Text = getHi();
    }

    private void button3_Click(object sender, EventArgs e)
    {
        const int maxsize = 2;
        String[] headerList = new String[maxsize];
        int len = getHeaderListTwo(maxsize, ref headerList);
        MessageBox.Show("Got length " + headerList.Length+" ("+len+")");
        label1.Text="";
        for (int i = 0; i < headerList.Length; ++i)
        {
            if (headerList[i].Length>0)
            {
                label1.Text += headerList[i].ToString() + " // ";
            }
            else
            {
                label1.Text += " // ";
            }
        }
    }

    private void button4_Click(object sender, EventArgs e)
    {
        int maxColumns=5;
        int numberOfColumns = 0;
        columnType[] matrix = new columnType[maxColumns];
        for (int i = 0; i < maxColumns; ++i)
        {
            matrix[i] = new columnType();
        }
        matrix[0].numberOfRows = 1; // pick something just to see if we can get it back
        matrix[0].columnName = "ABC";
        // numberOfRows must be less than or equal to maxRows

        columnType2[] matrix2 = new columnType2[maxColumns];
        for (int i = 0; i < maxColumns; ++i)
        {
            matrix2[i] = new columnType2();
        }
        matrix2[0].numberOfRows = 1; // pick something just to see if we can get it back

        //uint sz = (uint)maxColumns*4;
        //IntPtr matrixIP = GlobalAlloc(GPTR, sz);
        //columnType[] matrix = matrixIP;

        //IntPtr pointerArr = Marshal.AllocHGlobal(maxColumns*4);

        //int result = getMatrixNumberOfRowsInColumnZero(maxColumns,matrix);
        //label1.Text = result.ToString();

        numberOfColumns = getMatrix(maxColumns, maxRows, ref matrix);
        label1.Text = matrix[0].columnName;

    }
}
}
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