Ole Dll

[OrangeHopper]

Right Gents, I need some help.

We provide a Windows program that runs as a service and exchanges messages between local clients and a central system.

We provide a .h, .lib and a .dll to developers so they can get their programs to exchange messages with our service.

Usually this isn't a problem for our clients because calling our functions from C, C++ or Visual Basic is easy.

Unfortnately, we now have a client who is using a third party product that appears to insist on external code being OLE compliant.

My experience of OLE is limited to its precursor DDE so I'm currently looking for the odd external spark of inspiration.

At the moment I'm not interested in how we might provide something - I want to keep our work to a minimum - so its there a way of jacketing traditional dll based functions so they are OLE compliant.

Also, could someone provide me with a code snippet to show how to call a dll hosted C function from C#. We have a pre-C# version of Visual Studio so I can't check it myself.

Any pointers (not references ) would be useful.

Thanks in anticipation.

[DimPrawn]

It's very easy.

If you have the code to call your c/c++ dll from VB6, then simply create a Visual Basic ActiveX DLL project and create wrapper methods and properties to call into the DLL.

VB6 automatically creates the necessary type libraries for COM callers.

Your clients simply need to register the wrapper (run RegSvr32.exe) and have the VB6 wrapper and C dll in the same directory.

HTH

PS OLE is the old (like ancient man) term for ActiveX, which in turn is M$ marketing speak for COM (Component Object Model)

PPS Calling umanaged C/C++/Delphi DLL's from C# is known as PInvoke (Platform Invoke). See http://www.pinvoke.net/ and http://www.paulyao.com/resources/tools/pinvoke.asp

[OrangeHopper]

Many, many thanks Dim.

Much appreciated.