Using a .Net DLL in a COM Application 1

[davewelsh]

I want to create a DLL in VB .Net and use it in a COM program (VFP 6.0, actually). I don't really know where to start. I've read through the MSDN library on the subject but, I can't figure it out.

Can someone give an example of a VB.Net or C# DLL that can be used by COM? Also what special steps are required to build the project (commandline or IDE)?

 

[chiph]

Do a search in the docs for COM Interop. Also look for "CCW", which stands for COM Callable Wrapper.

Chip H.

 

[davewelsh]

Thanks. I read a few pages on CCW AND RCW. My aaembly is now in the GAC and it's registered for COM. Now my VFP 6.0 app recognizes the DLL but when I call CreateObject I get OLE error code 0x80131522: Unknown COM status code.

To simplify things, my .Net code is now just this:

<System.Runtime.InteropServices.ComVisible(True)> Public Class QMail

End Class

In FoxPro I have:

PROCEDURE test
  oMail = CreateObject("Quality.Mail")

 

[davewelsh]

This is supposed to mean that the COM client can't find the DLL. I have both put the assembly in the global assembly cache AND copied the DLL to the client's directory, but I still get the error.

 

[davewelsh]

Ok...

After rebooting it all works well.

 

[chiph]

Glad you got it working.

Chip H.