We have a .Net DLL. We need to call this DLL from a VB Application. What are the procedures we need to follow?
A:
The last time I did this, it got so thorny (some irrelevant issues involving COM+, deployment, etc tripping us up) that I actually ditched the COM boundary, and re-wrote the interface as a POX web-service talking to a handler (ashx) in the .NET. I would give serious consideration to this approach... (unless you need to share windows handles, or similar)
If you really want a COM API, you need to generate a COM-callable wrapper; this is largely a case of:
- ensuring the necessary types / methods are public
- marking the assembly / types as
[ComVisible(true)] - using
tlbexeto export the type library if you need - using
regasmto register the type in COM (either in the GAC or from a fixed location on a drive)
After that your VB6 should just see it as another COM package, but I strongly recommend that you limit this interface to the bare minimum; it isn't change-friendly, and the VB6-style interface forwarding (i.e. where you can get away with adding a method, without breaking binary compatibility) is not here.
Marc Gravell
2010-01-27 06:43:28
Same steps we follow and finally we got the issue in VB application Compile error user defined type not definied
subramani
2010-01-27 06:58:55
@subramani - does it list the reference in the VB6 IDE? And are you referencing the concrete type or the interface?
Marc Gravell
2010-01-27 07:34:47
YES its shows in References. public class
subramani
2010-01-27 08:16:01