Programming Forums > Application Development > C++

Klipt · Dec 5th, 2006, 12:03 PM

Wasn't sure whether to put this in the this forum or the C# one ... anyway...

Is it possible to write a nice user interface in C# but get it to call a number-crunching routine written in C++ (and compiled to native code, rather than bytecode)? Can Visual Studio 2005 version still compile its C++ code natively or is everything tied CLI runtime now? (If not, I suppose I'll have to look into mingw's DLL capabilities...)

The only info I've found about code mixing so far involves DLL's. I think I've got the C# part working (see end of the post - it's supposed to call a function from the DLL which as an experiment should do what the commented out C# code did)

But I'm not sure how to create the DLL in the first place. The new project wizard seems to give options for 'MFC DLL's and 'COM DLL's and so on ... is it possible to compile a 'normal' DLL?

Or even better, is there a way to do this without DLLs?

 csharp Syntax (Toggle Plain Text) 
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Drawing.Imaging;
using System.Text;
using System.Windows.Forms;
using System.Runtime.InteropServices;
 
namespace DLLUser
{
    public partial class frmDLLUser : Form
    {
        Bitmap bmp;
        Graphics gr;
        Random rand;
 
        public frmDLLUser()
        {
            InitializeComponent();
        }
 
        private void Form1_Load(object sender, EventArgs e)
        {
            bmp = new Bitmap(100, 100);
            gr = pnlPaint.CreateGraphics();
            rand = new Random();
        }
 
        [StructLayout(LayoutKind.Sequential, Pack = 1)]
        private struct STRUCT_DLL
        {
            public IntPtr scan0;
            public Int32 width;
            public Int32 height;
            public Int32 stride;
        }
 
        [DllImport("draw_dll.dll")]
        private static extern void func_dll(
            ref STRUCT_DLL s
         );                
 
        private void btnRand_Click(object sender, EventArgs e)
        {
            BitmapData data = bmp.LockBits(new Rectangle(0, 0, bmp.Width, bmp.Height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);
 
            STRUCT_DLL struct_dll = new STRUCT_DLL();
            struct_dll.scan0 = data.Scan0;
            struct_dll.width = data.Width;
            struct_dll.height = data.Height;
            struct_dll.stride = data.Stride;
 
            func_dll(ref struct_dll);
 
            /*unsafe
            {
                byte* imgPtr = (byte*)(data.Scan0);
                for (int i = 0; i < data.Height; i++)
                {
                    for (int j = 0; j < data.Width; j++)
                    {
                        *imgPtr = (byte)rand.Next(256);
                        *(imgPtr + 1) = (byte)rand.Next(256);
                        *(imgPtr + 2) = (byte)rand.Next(256);
 
                        imgPtr += 3;
                    }
                    imgPtr += data.Stride - data.Width * 3;
                }
            }*/
 
            bmp.UnlockBits(data);
 
            gr.DrawImage(bmp, new Point(0, 0));
        }
 
        private void pnlPaint_Paint(object sender, PaintEventArgs e)
        {
            gr.DrawImage(bmp, new Point(0, 0));
        }
    }
}
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Drawing.Imaging;
using System.Text;
using System.Windows.Forms;
using System.Runtime.InteropServices;

namespace DLLUser
{
    public partial class frmDLLUser : Form
    {
        Bitmap bmp;
        Graphics gr;
        Random rand;
        
        public frmDLLUser()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            bmp = new Bitmap(100, 100);
            gr = pnlPaint.CreateGraphics();
            rand = new Random();
        }

        [StructLayout(LayoutKind.Sequential, Pack = 1)]
        private struct STRUCT_DLL
        {
            public IntPtr scan0;
            public Int32 width;
            public Int32 height;
            public Int32 stride;
        }

        [DllImport("draw_dll.dll")]
        private static extern void func_dll(
            ref STRUCT_DLL s
         );                

        private void btnRand_Click(object sender, EventArgs e)
        {
            BitmapData data = bmp.LockBits(new Rectangle(0, 0, bmp.Width, bmp.Height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);

            STRUCT_DLL struct_dll = new STRUCT_DLL();
            struct_dll.scan0 = data.Scan0;
            struct_dll.width = data.Width;
            struct_dll.height = data.Height;
            struct_dll.stride = data.Stride;

            func_dll(ref struct_dll);

            /*unsafe
            {
                byte* imgPtr = (byte*)(data.Scan0);
                for (int i = 0; i < data.Height; i++)
                {
                    for (int j = 0; j < data.Width; j++)
                    {
                        *imgPtr = (byte)rand.Next(256);
                        *(imgPtr + 1) = (byte)rand.Next(256);
                        *(imgPtr + 2) = (byte)rand.Next(256);

                        imgPtr += 3;
                    }
                    imgPtr += data.Stride - data.Width * 3;
                }
            }*/

            bmp.UnlockBits(data);

            gr.DrawImage(bmp, new Point(0, 0));
        }

        private void pnlPaint_Paint(object sender, PaintEventArgs e)
        {
            gr.DrawImage(bmp, new Point(0, 0));
        }
    }
}

(places I've looked:
http://www.adp-gmbh.ch/csharp/call_dll.html
http://www.codersource.net/csharp_image_Processing.aspx for the bitmap stuff)

Narue · Dec 5th, 2006, 12:20 PM

You can mix and match .NET languages, so an assembly written in C++/CLI will mesh with an assembly written in C#. However, if you want to mix native C++ with a .NET assembly, you pretty much need to create a DLL in C++ and then uglify your C# to connect to it.

Klipt · Dec 5th, 2006, 1:03 PM

Yes, it looks like things will get ugly...

It seems that to create a 'normal' DLL you have to create a C++ 'console project' and then select the DLL option, instead of being distracted by all the things that mention DLLs on the first step.

All hail the great Microsoft for making things easy to find.

Klipt · Dec 5th, 2006, 1:35 PM

Woah, that last link I found actually got it working

IT'S ALIVE!

Thanks for the input.

Polyphemus_ · Dec 5th, 2006, 5:37 PM

You could use Managed C++ as well. Managed C++ uses the .NET framework, but can be integrated very easily with native C++ (even in the same source file), by using the #pragma unmanaged tags.

I use it myself now for a relatively big project, and it works like a charm: the ease of use of the .NET framework and the speed of native code. No ugly DLL function declarations or anything - it just works.

Klipt · Dec 7th, 2006, 10:09 AM

Thanks, I'll look into that.

Klipt · Dec 12th, 2006, 12:45 PM

Ok, I added and referenced a C++ project in a C# solution, and it compiles fine, but when it tries to access the C++ code during runtime it says:

System.IO.FileLoadException was unhandled
Message="Attempt to load an unverifiable executable with fixups (IAT with more than 2 sections or a TLS section.) (Exception from HRESULT: 0x80131019)"

I tried putting the C# call in an 'unsafe' block but it made no difference. Any ideas as to where I'm being stupid? :p

The C# code is in a button click event:

 csharp Syntax (Toggle Plain Text) 
Adder b;
int c = b.add1(5);
btnClick.Text = c.ToString();
Adder b;
int c = b.add1(5);
btnClick.Text = c.ToString();

C++ header:

 cpp Syntax (Toggle Plain Text) 
#ifndef CALC_H
#define CALC_H
 
#pragma managed
 
public value class Adder
{
public:
	int add1(int a);
};
 
#endif
#ifndef CALC_H
#define CALC_H

#pragma managed

public value class Adder
{
public:
	int add1(int a);
};

#endif

C++ code:

 cpp Syntax (Toggle Plain Text) 
#include "Calc.h"
#include <iostream>
 
#pragma managed
 
int Adder::add1(int a)
{
	return a+1;
}
 
int Main()
{
	return 0;
}
#include "Calc.h"
#include <iostream>

#pragma managed

int Adder::add1(int a)
{
	return a+1;
}

int Main()
{
	return 0;
}

Klipt · Dec 12th, 2006, 1:05 PM

I changed a compiler option for the C++ project to "Pure MSIL Common Language Runtime Support (/clr : pure)" and now it works. But now the assembly can't contain unmanaged code...

I assume this means that C# can't interface nicely with mixed C++ assemblies - you'd have to wrap the mixed C++ with another "pure MSIL" C++ class and only call the "pure MSIL" wrapper from C#? ---EDIT - seems to give the same error.

Or ditch the C# and use a 'windows forms' managed C++ GUI?

Polyphemus_ · Dec 12th, 2006, 1:35 PM

Yes, I suggest dropping C# and doing everything in C++/CLI. Almost the same as it uses the same framework, and it makes things a lot easier.

Klipt · Dec 12th, 2006, 3:16 PM

Hmm ... ease of Delphi and power of C++ ... very tempting

I finally found what I was doing wrong above: trying to link to a mixed .exe. I changed the C++ project to a DLL and it worked fine. So it seems C# can link easily to a mixed or pure .dll, but only to a pure .exe. Writing a managed wrapper for the unmanaged functions only saves you from [importing functions explicitly].

Dec 5th, 2006, 12:03 PM	#1
Klipt Hobbyist Programmer Join Date: Dec 2005 Posts: 118 Rep Power: 0	Combining C++ and C# Wasn't sure whether to put this in the this forum or the C# one ... anyway... Is it possible to write a nice user interface in C# but get it to call a number-crunching routine written in C++ (and compiled to native code, rather than bytecode)? Can Visual Studio 2005 version still compile its C++ code natively or is everything tied CLI runtime now? (If not, I suppose I'll have to look into mingw's DLL capabilities...) The only info I've found about code mixing so far involves DLL's. I think I've got the C# part working (see end of the post - it's supposed to call a function from the DLL which as an experiment should do what the commented out C# code did) But I'm not sure how to create the DLL in the first place. The new project wizard seems to give options for 'MFC DLL's and 'COM DLL's and so on ... is it possible to compile a 'normal' DLL? Or even better, is there a way to do this without DLLs? csharp Syntax (Toggle Plain Text) using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Drawing.Imaging; using System.Text; using System.Windows.Forms; using System.Runtime.InteropServices; namespace DLLUser { public partial class frmDLLUser : Form { Bitmap bmp; Graphics gr; Random rand; public frmDLLUser() { InitializeComponent(); } private void Form1_Load(object sender, EventArgs e) { bmp = new Bitmap(100, 100); gr = pnlPaint.CreateGraphics(); rand = new Random(); } [StructLayout(LayoutKind.Sequential, Pack = 1)] private struct STRUCT_DLL { public IntPtr scan0; public Int32 width; public Int32 height; public Int32 stride; } [DllImport("draw_dll.dll")] private static extern void func_dll( ref STRUCT_DLL s ); private void btnRand_Click(object sender, EventArgs e) { BitmapData data = bmp.LockBits(new Rectangle(0, 0, bmp.Width, bmp.Height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb); STRUCT_DLL struct_dll = new STRUCT_DLL(); struct_dll.scan0 = data.Scan0; struct_dll.width = data.Width; struct_dll.height = data.Height; struct_dll.stride = data.Stride; func_dll(ref struct_dll); /unsafe { byte imgPtr = (byte)(data.Scan0); for (int i = 0; i < data.Height; i++) { for (int j = 0; j < data.Width; j++) { imgPtr = (byte)rand.Next(256); (imgPtr + 1) = (byte)rand.Next(256); (imgPtr + 2) = (byte)rand.Next(256); imgPtr += 3; } imgPtr += data.Stride - data.Width * 3; } }/ bmp.UnlockBits(data); gr.DrawImage(bmp, new Point(0, 0)); } private void pnlPaint_Paint(object sender, PaintEventArgs e) { gr.DrawImage(bmp, new Point(0, 0)); } } } using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Drawing.Imaging; using System.Text; using System.Windows.Forms; using System.Runtime.InteropServices; namespace DLLUser { public partial class frmDLLUser : Form { Bitmap bmp; Graphics gr; Random rand; public frmDLLUser() { InitializeComponent(); } private void Form1_Load(object sender, EventArgs e) { bmp = new Bitmap(100, 100); gr = pnlPaint.CreateGraphics(); rand = new Random(); } [StructLayout(LayoutKind.Sequential, Pack = 1)] private struct STRUCT_DLL { public IntPtr scan0; public Int32 width; public Int32 height; public Int32 stride; } [DllImport("draw_dll.dll")] private static extern void func_dll( ref STRUCT_DLL s ); private void btnRand_Click(object sender, EventArgs e) { BitmapData data = bmp.LockBits(new Rectangle(0, 0, bmp.Width, bmp.Height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb); STRUCT_DLL struct_dll = new STRUCT_DLL(); struct_dll.scan0 = data.Scan0; struct_dll.width = data.Width; struct_dll.height = data.Height; struct_dll.stride = data.Stride; func_dll(ref struct_dll); /unsafe { byte* imgPtr = (byte)(data.Scan0); for (int i = 0; i < data.Height; i++) { for (int j = 0; j < data.Width; j++) { imgPtr = (byte)rand.Next(256); (imgPtr + 1) = (byte)rand.Next(256); (imgPtr + 2) = (byte)rand.Next(256); imgPtr += 3; } imgPtr += data.Stride - data.Width * 3; } }*/ bmp.UnlockBits(data); gr.DrawImage(bmp, new Point(0, 0)); } private void pnlPaint_Paint(object sender, PaintEventArgs e) { gr.DrawImage(bmp, new Point(0, 0)); } } } (places I've looked: http://www.adp-gmbh.ch/csharp/call_dll.html http://www.codersource.net/csharp_image_Processing.aspx for the bitmap stuff) __________________ Get PLT Scheme\|SB Common Lisp\|Haskell\|wxDev-C++\|Python

Dec 5th, 2006, 12:20 PM	#2
Narue Professional Programmer Join Date: Sep 2005 Posts: 419 Rep Power: 3	You can mix and match .NET languages, so an assembly written in C++/CLI will mesh with an assembly written in C#. However, if you want to mix native C++ with a .NET assembly, you pretty much need to create a DLL in C++ and then uglify your C# to connect to it. __________________ Even if the voices aren't real, they have some pretty good ideas.

Dec 5th, 2006, 1:03 PM	#3
Klipt Hobbyist Programmer Join Date: Dec 2005 Posts: 118 Rep Power: 0	Yes, it looks like things will get ugly... It seems that to create a 'normal' DLL you have to create a C++ 'console project' and then select the DLL option, instead of being distracted by all the things that mention DLLs on the first step. All hail the great Microsoft for making things easy to find. __________________ Get PLT Scheme\|SB Common Lisp\|Haskell\|wxDev-C++\|Python

Dec 5th, 2006, 1:35 PM	#4
Klipt Hobbyist Programmer Join Date: Dec 2005 Posts: 118 Rep Power: 0	Woah, that last link I found actually got it working IT'S ALIVE! Thanks for the input. __________________ Get PLT Scheme\|SB Common Lisp\|Haskell\|wxDev-C++\|Python

Dec 7th, 2006, 10:09 AM	#6
Klipt Hobbyist Programmer Join Date: Dec 2005 Posts: 118 Rep Power: 0	Thanks, I'll look into that. __________________ Get PLT Scheme\|SB Common Lisp\|Haskell\|wxDev-C++\|Python

Dec 5th, 2006, 5:37 PM	#5
Polyphemus_ Expert Programmer Join Date: Aug 2005 Location: Rotterdam, the Netherlands Posts: 942 Rep Power: 4	You could use Managed C++ as well. Managed C++ uses the .NET framework, but can be integrated very easily with native C++ (even in the same source file), by using the #pragma unmanaged tags. I use it myself now for a relatively big project, and it works like a charm: the ease of use of the .NET framework and the speed of native code. No ugly DLL function declarations or anything - it just works.

Dec 12th, 2006, 12:45 PM	#7
Klipt Hobbyist Programmer Join Date: Dec 2005 Posts: 118 Rep Power: 0	Ok, I added and referenced a C++ project in a C# solution, and it compiles fine, but when it tries to access the C++ code during runtime it says: System.IO.FileLoadException was unhandled Message="Attempt to load an unverifiable executable with fixups (IAT with more than 2 sections or a TLS section.) (Exception from HRESULT: 0x80131019)" I tried putting the C# call in an 'unsafe' block but it made no difference. Any ideas as to where I'm being stupid? :p The C# code is in a button click event: csharp Syntax (Toggle Plain Text) Adder b; int c = b.add1(5); btnClick.Text = c.ToString(); Adder b; int c = b.add1(5); btnClick.Text = c.ToString(); C++ header: cpp Syntax (Toggle Plain Text) #ifndef CALC_H #define CALC_H #pragma managed public value class Adder { public: int add1(int a); }; #endif #ifndef CALC_H #define CALC_H #pragma managed public value class Adder { public: int add1(int a); }; #endif C++ code: cpp Syntax (Toggle Plain Text) #include "Calc.h" #include <iostream> #pragma managed int Adder::add1(int a) { return a+1; } int Main() { return 0; } #include "Calc.h" #include <iostream> #pragma managed int Adder::add1(int a) { return a+1; } int Main() { return 0; } __________________ Get PLT Scheme\|SB Common Lisp\|Haskell\|wxDev-C++\|Python

Dec 12th, 2006, 1:05 PM	#8
Klipt Hobbyist Programmer Join Date: Dec 2005 Posts: 118 Rep Power: 0	I changed a compiler option for the C++ project to "Pure MSIL Common Language Runtime Support (/clr : pure)" and now it works. But now the assembly can't contain unmanaged code... I assume this means that C# can't interface nicely with mixed C++ assemblies - you'd have to wrap the mixed C++ with another "pure MSIL" C++ class and only call the "pure MSIL" wrapper from C#? ---EDIT - seems to give the same error. Or ditch the C# and use a 'windows forms' managed C++ GUI? __________________ Get PLT Scheme\|SB Common Lisp\|Haskell\|wxDev-C++\|Python Last edited by Klipt; Dec 12th, 2006 at 1:22 PM.

Dec 12th, 2006, 1:35 PM	#9
Polyphemus_ Expert Programmer Join Date: Aug 2005 Location: Rotterdam, the Netherlands Posts: 942 Rep Power: 4	Yes, I suggest dropping C# and doing everything in C++/CLI. Almost the same as it uses the same framework, and it makes things a lot easier.

Dec 12th, 2006, 3:16 PM	#10
Klipt Hobbyist Programmer Join Date: Dec 2005 Posts: 118 Rep Power: 0	Hmm ... ease of Delphi and power of C++ ... very tempting I finally found what I was doing wrong above: trying to link to a mixed .exe. I changed the C++ project to a DLL and it worked fine. So it seems C# can link easily to a mixed or pure .dll, but only to a pure .exe. Writing a managed wrapper for the unmanaged functions only saves you from [importing functions explicitly]. __________________ Get PLT Scheme\|SB Common Lisp\|Haskell\|wxDev-C++\|Python

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Programming Forums > Application Development > C++

Combining C++ and C#