Pass Optional Arguments to MFC ActiveX Controls

[Guest]

Hi.

I have an ActiveX control created by MFC.
One method has the following definition:

[id(1), helpstring("method MyMethod")] SHORT MyMethod(BSTR p1, [optional]
VARIANT p2, [optional] VARIANT p3);

In VB6, I can call this method by the following three ways:

1. MyMethod(p1)
2. MyMethod(p1, p2)
3. MyMethod(p1, p2, p3)

But in VB.NET, only the first and third call can be done.
When I write code like the second one, VS.NET says "Overload resolution
failed because no accessible 'MyMethod' accepts this number of arguments".
It seems I must call this mehod with

MyMethod(p1, p2, Type.Missing)

What's wrong? Or I can not use the second call at all in VB.NET?

Any suggestion will be appreciated.
Thank you in advance.

An

 

[Guest]

Change 'variant' to another type

Me personally have always only ever written non-MFC DLL's in C++ & called
them from VB/VB.NET

What type is the defaults for 'variant'?

 

[Guest]

Thanks for your reply.

I have read an article from msdn, it says the optional parameter must be of
type VARIANT.

http://support.microsoft.com/kb/q154039/

 

[Guest]

In VB.NET you don't have the 'Variant' data type.

What is your MFC DLL library name?

What is the function name you are trying to call?

I have found an article that maybe of some help to you (MFC):

http://www.codeproject.com/dll/BSTR_CString_conversion.asp

Let me know the answers to my questions & if the above article helped

 

[Guest]

I thought I remember reading somewhere that DLL's written in MFC aren't
compatible with VB.Net but I could be wrong (I seem to be wrong a lot when it
comes to VB.Net).