very simple function for using in C#

Question

Hi all

I am very new with C++ and I am trying to build a function in C++
to use in C#

When I do this it works fine, but the code is now in the header file:
// cClassLibrary.h

#pragma once

using namespace System;

namespace cClassLibrary
{
public ref class Class1
{
public:
int DoSomething(int a, int b)
{return a + b;}
};
}

When I try to use the .cpp file, I cannot get it to work ...
I am able to compile, but I cannot see my method in C#.
What am I doing wrong ??

Thanks for any help.
Regards, Frank

 

// cClassLibrary.h

#pragma once

using namespace System;

namespace cClassLibrary{ public class Class1
{
public:
int DoSomething(int a, int b);
};
}

 

// This is the main DLL file.

#include "stdafx.h"

#include "cClassLibrary.h"

int DoSomething(int a, int b)
{
return a + b;
}

Answer 1

Change to:

int Class1::DoSomething(int a, int b)
{
    return a + b;
}

Answer 2

Now I get this exception:
error C2653: 'Class1' : is not a class or
namespace name

Regards
Frank

Answer 3

Then add namespace:

namespace cClassLibrary
{
    int Class1::DoSomething(int a, int b)
    {
        return a + b;
    }
}

or add using directive.

Answer 4

Thanks, I am getting closer :-)
I tried "cClassLibrary.Class1::DoSomething" ...

Now I am able to compile,
but the DoSomething function is not visible in C# ...

Regards
Frank

Answer 5

Make sure Class1 is defined with “public ref class” and DoSomething is after “public:”.

Answer 6

great, that's it !
Thanks a lot ! :-)

Regards
Frank

Answer 7

Sorry, I just have a very little additional question:
In the context of declaration variables, what does ^ mean ??
I guess % means something like C# ref ?

System::Data::SqlClient::SqlConnection ^%_SqlConnection,
System::String ^_Query,
System::String ^_DataTableName

Answer 8

Sorry, I just have a very little additional question:
In the context of declaration variables, what does ^ mean ??
I guess % means something like C# ref ?
 
System::Data::SqlClient::SqlConnection ^%_SqlConnection,
System::String ^_Query,
System::String ^_DataTableName

The hat denotes a "managed handle", which is like a moveable pointer. In Managed C++ (the predecessor of C++/CLI) both managed and unmanaged poinetrs were denoted by *, which could (and did) get confusing.
 
An excellent book on C++/CLI is Nishant Sivakumar's "C++/CLI in Action".
 

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David Wilkinson | Visual C++ MVP