Passing array of strings from C# to C++ Com

Question

I have requirement of passing an array of strings from a C# module to my C++ COM component. The following is the idl declaration;

[id(11), helpstring("method deleteObjectsEx")] HRESULT deleteObjectsEx(
                [in] BSTR userName,
                [in] BSTR userPasswd, 
                [in] SAFEARRAY(VARIANT) varValues, 
                [in] BSTR deleteMode
                );

And from the C# we use the following code to invoke the API

List<string> ObjectIDS = new List<string>();
ObjectIDS.Add(obj._ObjectId[0]);
ObjectIDS.Add(obj._ObjectId[1]);

/*Array ar = Array.CreateInstance(typeof(string), size);
ar.SetValue(obj._ObjectId[0], 0);
ar.SetValue(obj._ObjectId[1], 1);*/

mhubBridge.deleteObjectsEx(Encrypt(auth.UserName), 
                           Encrypt(auth.UserPassword), 
                           ObjectIDS.ToArray(),
                           obj._delMEthod);

On invoking the deleteObjectsEx API i get "A first chance exception of type System.Runtime.InteropServices.SafeArrayTypeMismatchException occurred in IPDWebService.DLL IPDWS::trace::(Tuesday, 06 August 2013 13:27): Exception in deleteObjectsEx:: message - Specified array was not of the expected type.

What is the C# declaration of deleteObjectsEx ? (if you imported the .tlb, one has probably been auto-generated) — Medinoc
– Medinoc, Commented Aug 6, 2013 at 9:18
@Medinoc its public virtual void deleteObjectsEx(string userName, string userPasswd, Array varValues, string deleteMode); — sameer karjatkar
– sameer karjatkar, Commented Aug 6, 2013 at 9:20
@xantos Sorry for the extra code ...i was trying out different combinations — sameer karjatkar
– sameer karjatkar, Commented Aug 6, 2013 at 9:39

xanatos · Accepted Answer · 2013-08-06 10:03:35Z

1

(not working)

Try using the ar array.

mhubBridge.deleteObjectsEx(Encrypt(auth.UserName), 
                           Encrypt(auth.UserPassword), 
                           ar,
                           obj._delMEthod);

If it works, remove all the ObjectIDS "things".

or try:

(working)

object[] ar = new object[] { obj._ObjectId[0], obj._ObjectId[1] };

and pass it to the deleteObjectsEx(...)

because technically a VARIANT is an object, so a SAFEARRAY(VARIANT) is an object[].

edited Aug 6, 2013 at 10:03

answered Aug 6, 2013 at 9:39

xanatos

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xanatos Over a year ago

@sameerkarjatkar Try the object[] (second example). Remember to pass it to the deleteObjectsEx!

AndiKrue · Accepted Answer · 2016-09-24 12:27:44Z

0

Try this:

object[] ar = new object[2];
ar [0] = obj._ObjectId[0];
ar [1] = obj._ObjectId[1];

answered Sep 24, 2016 at 12:27

AndiKrue

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