Invoke a (ActiveX-)method that takes a refnum (Interface-ID) as argument

[De_Sa]

Hi there,

I have created an ActiveX-Object that exposes a method for creating other objects by name and that would return a pointer to the interface I also specify. In C++, this works perfectly - the function declaration looks like this (IDL): HRESULT GetSubSystem([in] BSTR aName, [in] REFIID IId, [out,retval] IUnknown** aInterface);

I have also succeeded in creating this object with LABView, but when I try to create the invoke-method node from the object, this method name is grayed out. Therefore it seems that I have no chance to call this function. Is this by intention, or am I doing something wrong ??

As a workaround I added another function, that would accept the Interface Id as a String (IDL-function declaration): HRESULT GetSubSystemEx([in] BSTR aName, [in] BSTR InterfaceId, [out,retval] IUnknown** aInterface); Now using this method in LABView works as expected, but this brings in another issue:

Can I convert the output on an AutomationRefnum-Node to a String that contains the GUID of that Refnum ??

Anyone some suggestions ? Thanks for any help !

[TSP]

Hi,

for your work around (also for your primer solution) you need a method to call the value from your activeX object...

LabVIEW works by exchanging datas by value, but you are doing this be references within this activeX call.

I would suggest you to change your activeX component (if it is possible) from "pass by reference" to "pass by value"

or later to integrate a invoke node where you can call the value stored by the provided address...

Hope this helps you!