ActiveX Dll's

[Jeff Crumb]

Has anyone out there ever written a dll using VB? If so, can those same dll's be accessed from a program other then Visual Basic? Is there a web site that has some sample dll code that I can look at?

I admit that I have never written a dll, so I am not sure how to start since there doesn't seem to be a lot of documentation on it.

Thanks a lot,

[Serge]

MSDN has tons of examples on how to create your first ActiveX DLL.

Here can be your first step

[honeybee]

I have used ActiveX DLLs in VB. But not sure whether they will work with any other programs.

I guess the structure of DLLs in VB and in C is a bit different. In VB you have to have a class in your DLL, while in C you can just combine different functions into a DLL.

I would like to know this, too.

[agent]

Yes c(++) dlls are different from VB dlls. However, they are cross-compatible. VC++ can use ActiveX dlls, and vb can use C(++) dlls. Come to think of it, ActiveX dlls, while less numerous, are supported by more programming languages than I care to think of.

It might also be important to note that dlls only usually work under windows.

The DLL's created in VB are COM DLL's, which means they internally implement the COM interface. THis means that any language that can use COM components (ie: VB, VC++, Delphi, ObjectAda etc.) can access your DLL.

VC++ also has the ability to create non-COM DLL's which you can't do in VB. the non-COM dll's are just collections of functions that you can call - which are declared and used the same waythat you use an API call (which is just accessing a function in a non-COM C DLL).

(NB. COM is effectively the same thing as ActiveX)

- gaffa