Passing string array from Borland C++ to C# - com

Question

I want to pass list of email address strings from Borland C++ to my C# library. Below my C# side code. I could make call to PrintName() method and it works. Now I want to print email addresses, but if I call PrintEmails() function nothing happens. Could you please suggest how I can pass multiple email addresses to C# lib.
[ComVisible(true)]
[InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
[Guid("4A686AB1-8425-43D9-BD89-B696BB5F6A18")]
public interface ITestConnector
{
void PrintEmails(string[] emails);
void PrintName(string name);
}
[ComVisible(true)]
[ClassInterface(ClassInterfaceType.None)]
[ComDefaultInterface(typeof(ITestConnector))]
[Guid("7D818287-298A-41BF-A224-5EAC9C581BD0")]
public class TestConnector : ITestConnector
{
public void PrintEmails(string[] emails)
{
System.IO.File.WriteAllLines(#"c:\temp\emails.txt", emails);
}
public void PrintName(string name)
{
System.IO.File.WriteAllText(#"c:\temp\name.txt", name);
}
}
I have imported TLB file of above C# library into RAD Studio and my C++ side code is as below.
interface ITestConnector : public IUnknown
{
public:
virtual HRESULT STDMETHODCALLTYPE PrintEmails(LPSAFEARRAY* emails/*[in,out]*/) = 0; // [-1]
virtual HRESULT STDMETHODCALLTYPE PrintName(WideString name/*[in]*/) = 0; // [-1]
};
TTestConnector *connector = new TTestConnector(this);
SAFEARRAYBOUND bounds[] = {{2, 0}}; //Array Contains 2 Elements starting from Index '0'
LPSAFEARRAY pSA = SafeArrayCreate(VT_VARIANT,1,bounds); //Create a one-dimensional SafeArray of variants
long lIndex[1];
VARIANT var;
lIndex[0] = 0; // index of the element being inserted in the array
var.vt = VT_BSTR; // type of the element being inserted
var.bstrVal = ::SysAllocStringLen( L"abc#xyz.com", 11 ); // the value of the element being inserted
HRESULT hr= SafeArrayPutElement(pSA, lIndex, &var); // insert the element
// repeat the insertion for one more element (at index 1)
lIndex[0] = 1;
var.vt = VT_BSTR;
var.bstrVal = ::SysAllocStringLen( L"pqr#xyz.com", 11 );
hr = SafeArrayPutElement(pSA, lIndex, &var);
connector->PrintEmails(pSA);
delete connector;

Answer 1

Below C++ side code worked in my case.
SAFEARRAYBOUND saBound[1];
saBound[0].cElements = nElements;
saBound[0].lLbound = 0;
SAFEARRAY *pSA = SafeArrayCreate(VT_BSTR, 1, saBound);
if (pSA == NULL)
{
return NULL;
}
for (int ix = 0; ix < nElements; ix++)
{
BSTR pData = SysAllocString(elements[ix]);
long rgIndicies[1];
rgIndicies[0] = saBound[0].lLbound + ix;
HRESULT hr = SafeArrayPutElement(pSA, rgIndicies, pData);
_tprintf(TEXT("%d"), hr);
}