Question

I have to replace an existing dll call that is registered and called using RegFn and CallFn respectively.

I am trying to write the dll using C# in the hope that as long as the function signature match and the dll is in the right place it will work.

so

pnHndl= RegFn("CALCULATE", "I", "I", "AJons.DLL")
pnRetVal = CallFn(pnHndl, 0)

My code is as follows:

[Guid("EAB7C2CD-2471-4BDA-90E9-F70403BAA557")]
[ComVisible(true)]
public class AJons : _AJons
{

    [ComVisible(true)]
    public int CALCULATE(int value)
    {
        return value * 2;
    }

}

Foxpro doesn’t play ball I just get ‘could not load library AJon.dll’

Does anyone have any experience here?

Cheers.

Answer 1

From what I can see, those really old RegFn and CallFn are for calling Win32 native Dlls – completely different from COM.

What you need to create a Win32 dll that will work with those functions is C++.

What you should do (if you HAVE to keep using FoxPro) is at least use the latest version of VFP.

written on my iPhone

Update 1

1) Just in case I wasn’t clear, you cannot make this kind of DLL from .NET.

2) Have a look at this link here for a very simple example of how to write a Win32 dll.