How do I show image read by opecv by using a c# interface

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C++/CLI

C#

DLL

OpenCV

Hi everyone,

I am stdying on running c++ codes with a c# interace. I have tried something and now a can return for example "52" to c# interface and write "52 "to a textbox. My problem occurs when i want to show an image that read by opencv library functions.

That is the NativeLib.c for printing something and showing image on a window

#include "stdafx.h"
#include "NativeLib.h"
#include <stdio.h>
#include "opencv2/core/core.hpp"
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include "iostream"
#include <string.h>
using namespace cv;
using namespace std;

MYAPI int print_line(const char* str) {
	return 52;
}
MYAPI void ShowImage()
{
    Mat image;
    image = imread("aile.jpg", CV_LOAD_IMAGE_COLOR); 
    namedWindow( "Display window", WINDOW_AUTOSIZE );// Create a window for display.
    imshow( "Display window", image );   
}


That is NativeLib.h
#ifndef _NATIVELIB_H_
#define _NATIVELIB_H_

#ifndef MYAPI
#define MYAPI
#endif

#ifdef __cplusplus
extern "C"{
#endif


MYAPI int print_line(const char* str);
MYAPI void ShowImage();

#ifdef __cplusplus
}
#endif

#endif // _NATIVELIB_H_

That is c# interface

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;

namespace InterfaceForServer
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        [DllImport("bitirme2.dll", EntryPoint = "print_line")]
        private static extern int print_line(string str);

        [DllImport("bitirme2.dll", EntryPoint = "ShowImage")]
        public static extern void ShowImage();

        public void button1_Click(object sender, EventArgs e)
        {
            textBox1.Text = print_line("Hello, PInvoke!").ToString();
            ShowImage();
        }
    }
}

i can see "52" in the textBox, but while ShowImage is running it gives

An unhandled exception of type 'System.Runtime.InteropServices.SEHException' occurred in InterfaceForServer.exe

Additional information: External component has thrown an exception.

I have googled but everyone says there could be and error about dll. But as i told above print function is running well so i am not sure the problem is at dll. And also dll is generated after every rebuilt at the output directory, i determined.

The problem is occured in line

imshow( "Display window", image );

If there is nothing clear please post

Thanks