Passing SAFEARRAY of UDTs to a COM object

Hi there,
I am trying to interface with a legacy COM application from a Java client using
jCOM. One of the methods of the COM program takes an input which is a VARIANT
containg a SAFEARRAY of a custom type. The custom type is a simple structure
consisting of two 'doubles'.
The relevant bits of the IDL file looks like this (reverse engineered using OLEView):
uuid(19CFAB24-06AC-11D7-9C30-0050DA7B5DE3),
version(1.0),
helpstring("XXX 1.0 Type Library")
library XxxLib
// TLib : // TLib : OLE Automation : {00020430-0000-0000-C000-000000000046}
importlib("stdole2.tlb");
// Forward declare all types defined in this typelib
interface IXxx;
typedef [uuid(2EC68D72-0780-11D7-9C31-0050DA7B5DE3), helpstring("UNNAMED_POINT
struct")]
struct tagUNNAMED_POINT {
double latitude;
double longitude;
} UNNAMED_POINT;
uuid(19CFAB31-06AC-11D7-9C30-0050DA7B5DE3),
helpstring("Xxx Class")
coclass Xxx {
[default] interface IXxx;
odl,
uuid(19CFAB30-06AC-11D7-9C30-0050DA7B5DE3),
helpstring("IXxx Interface")
interface IXxx : IUnknown {
[helpstring("Set the points for a line symbol on the named overlay")]
HRESULT _stdcall SetLineSymbol(
[in] BSTR display_name,
[in] BSTR line_type,
[in] BSTR overlay_name,
[in] VARIANT points);
The parameter 'VARIANT points' is a SAFEARRAY containing an array of UNNAMED_POINTs.
The problem I am having is that the COM client returns COM error 0x80070057 -
Invalid arguments. Unfortunately I do not have access to the COM source code.
I have, however, tried creating a test utility with the same function prototype
so that I can debug it in Visual Studio. This shows that the VARIANT is being
sent correctly as a SAFEARRAY with the correct number of elements but the contents
of it are rubbish.
Has anyone else had this problem, or is there a way round it? We have accessed
the COM object successfully from a C++ client.
Thanks in advance,
Tim

Assuming you have the pieces of information that need to go into the array, convert each one into a variant using the built-in LV function. Next, combine all the resulting variants into an array using an array builder. Finally wire the array of variants to the com object terminal where you need it.
Mike...
Certified Professional Instructor
Certified LabVIEW Architect
LabVIEW Champion
"... after all, He's not a tame lion..."
Be thinking ahead and mark your dance card for NI Week 2015 now: TS 6139 - Object Oriented First Steps

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On 1/27/2015 7:43 PM, jdyng77 wrote:
I did some research on this issue to help me better understand your comments here. I still don't fully understand the problem. Please help me out. Or, if I can get around the problem by using IMoniker and IRunningObjectTable instead,
I would be more than happy doing that.
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Timothy Toroni wrote:
> Thanks for the info, however their example is labview server and
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>
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Passing SAFEARRAY of UDTs to a COM object

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