VC6 <-> C#(net 2.0) interaction

  • Thread starter Thread starter Guest
  • Start date Start date
G

Guest

Hi there.

We maintain a big VC6 project that we currently can´t convert to VS2005 for
various reasons. For our current project we need to establish a communication
channel between this VC6 project and another project that is running on
VS2005 C# and NET 2.0.

All our efforts so far were unsuccessful. Especially triggering events from
C++ to NET doesn´t work. We would be very thankfull for a set of sample
projects that actually interact VC6 <-> C#. Any help would be very
appreciated!

Thanks a lot!
 
Hi Elmar!
We maintain a big VC6 project that we currently can´t convert to VS2005 for
various reasons. For our current project we need to establish a communication
channel between this VC6 project and another project that is running on
VS2005 C# and NET 2.0.

All our efforts so far were unsuccessful. Especially triggering events from
C++ to NET doesn´t work. We would be very thankfull for a set of sample
projects that actually interact VC6 <-> C#. Any help would be very
appreciated!
Click to expand...

What is this VC6 project??? DLL/LIB/EXE/(In/Out)COM-Server ?

Greetings
Jochen
 
We maintain a big VC6 project that we currently can´t convert to VS2005
for
various reasons. For our current project we need to establish a
communication
channel between this VC6 project and another project that is running on
VS2005 C# and NET 2.0.

All our efforts so far were unsuccessful. Especially triggering events
from
C++ to NET doesn´t work. We would be very thankfull for a set of sample
projects that actually interact VC6 <-> C#. Any help would be very
appreciated!
Click to expand...

There are 2 ways:

1)build a plain C style DLL that communicates with your C++ app in whatever
way you see fit, and then consume that DLL in your .NET app.
..NET 2.0 has facilities for converting delegates to C style function
pointers so with some decent plumbing code, your should be able to make it
work.

2)build a .NET class library that communicates with your .NET app, and
register is for COM interop. then consume that COM class in your C++
application to work with the .NET application.

either way should work without too many problems.
 
Can we discuss this a little bit more?
Assuming I have a simple test class library with one class:

------
using System;
using System.Collections.Generic;
using System.Text;

namespace vc6interop
{
public class Interop
{
public static string GreetMe(string name)
{
return "Hallo " + name;
}
}
}
------

....that is compiled with "expose as COM" flag turned on.
What do I have to do in order to call this method in C++?

I found some code that would fit this sample but it gives me a lot of errors.

------
GreetMe function;
CString result;

HINSTANCE hinstLib = LoadLibrary("vc6interop.dll");

if (hinstLib) {

function = (GreetMe) GetProcAddress(hinstLib, "GreetMe");


if (function)
result = (function) ("John");


BOOL fFreeResult = FreeLibrary(hinstLib);
}

// Das Ergebnis anzeigen
if (!hinstLib || !function)
printf("Error\n");
else
printf("Result: %s\n", result);
 
Elmar said:
Can we discuss this a little bit more?
Assuming I have a simple test class library with one class:

------
using System;
using System.Collections.Generic;
using System.Text;

namespace vc6interop
{
public class Interop
{
public static string GreetMe(string name)
{
return "Hallo " + name;
}
}
}
------

...that is compiled with "expose as COM" flag turned on.
What do I have to do in order to call this method in C++?

I found some code that would fit this sample but it gives me a lot of
errors.
Click to expand...
Don't know what that means.

CString result;

HINSTANCE hinstLib = LoadLibrary("vc6interop.dll");
Click to expand...
Nope, only .NET framework can load a .NET assembly.

if (hinstLib) {

function = (GreetMe) GetProcAddress(hinstLib, "GreetMe");
Click to expand...
Nope, .NET code doesn't have an address until the JIT compiles it.

Instead, you must use CoInitialize to enable COM support in your
application, and CoCreateObject to create an instance of a .NET class. Then
you will be able to call the methods.
 
Back
Top