IIS authentication configuration with C++ code

I am trying to develop a C++ program to programmatically configure the IIS app host configuration file, but failed to add a element to the elementcollection.

And I kept getting an error complaining that another process is accessing the same data and do not know why.

Below is the code snippet.

Any kind of advice will be appreciated.

#include "stdafx.h"
#include <windows.h>
#include <stdio.h>
#include <ahadmin.h>
#include <crtdbg.h>
#include <string>

using namespace std;

void PrintPropertiesOfElement(IAppHostElement *pElement)
{
	HRESULT hr = S_OK;

	IAppHostPropertyCollection *pProperties = NULL;
	IAppHostProperty *pProperty = NULL;

	hr = pElement->get_Properties(&pProperties);

	DWORD properties_count = 0;
	hr = pProperties->get_Count(&properties_count);

	VARIANT vtIndex;
	vtIndex.vt = VT_INT;
	for(DWORD i=0; i<properties_count; ++i)
	{
		vtIndex.intVal = i;
		hr = pProperties->get_Item(vtIndex, &pProperty);

		BSTR strName;
		BSTR strValue;
		hr = pProperty->get_Name(&strName);
		hr = pProperty->get_StringValue(&strValue);
		_tprintf(_T("name : %s,  value: %s\n"), strName, strValue);
	}
}


void PrintElementsOfCollection(IAppHostChildElementCollection *pCollection)
{
	HRESULT hr = S_OK;

	IAppHostElement *pElement = NULL;

	DWORD elements_count = 0;
	hr = pCollection->get_Count(&elements_count);

	VARIANT vtIndex;
	vtIndex.vt = VT_INT;
	for(DWORD i=0; i<elements_count; ++i)
	{
		vtIndex.intVal = i;
		hr = pCollection->get_Item(vtIndex, &pElement);

		BSTR strName;
		hr = pElement->get_Name(&strName);
		_tprintf(_T("element : %s\n"), strName);
	}
}

void PrintElementsOfCollection(IAppHostElementCollection *pCollection)
{
	HRESULT hr = S_OK;

	IAppHostElement *pElement = NULL;

	DWORD elements_count = 0;
	hr = pCollection->get_Count(&elements_count);

	VARIANT vtIndex;
	vtIndex.vt = VT_INT;
	for(DWORD i=0; i<elements_count; ++i)
	{
		vtIndex.intVal = i;
		hr = pCollection->get_Item(vtIndex, &pElement);

		BSTR strName;
		hr = pElement->get_Name(&strName);
		_tprintf(_T("element : %s\n"), strName);

		//PrintPropertiesOfElement(pElement);
	}
}

struct UserCertification
{
	VARIANT username;
	VARIANT password;
	VARIANT certification;

public:
	UserCertification(wstring name, wstring pwd, wstring cert)
	{
		username.vt = VT_BSTR;
		username.bstrVal = SysAllocString(name.c_str());
		
		password.vt = VT_BSTR;
		password.bstrVal = SysAllocString(pwd.c_str());

		certification.vt = VT_BSTR;
		certification.bstrVal = SysAllocString(cert.c_str());
	}
};

HRESULT SetHostElementProperty(IAppHostElement *pElement, UserCertification *pUserCert)
{
	HRESULT hr = S_OK;

	IAppHostProperty *pProperty = NULL;

	BSTR name = SysAllocString(L"userName");
	BSTR password = SysAllocString(L"password");
	BSTR certification = SysAllocString(L"certificate");

	//name
	hr = pElement->GetPropertyByName(name, &pProperty);
	pProperty->put_Value(pUserCert->username);

	//password
	hr = pElement->GetPropertyByName(password, &pProperty);
	pProperty->put_Value(pUserCert->password);

	//certification
	hr = pElement->GetPropertyByName(certification, &pProperty);
	pProperty->put_Value(pUserCert->certification);

	return hr;
}

UserCertification* GenerateUserCertification()
{
	wstring username = L"jinqiu.tao@emacle.com";
	wstring password = L"123456";
	wstring certificate = L"xxxxxxxx";

	return new UserCertification(username, password, certificate);
}

int _tmain(int argc, _TCHAR* argv[])
{
	HRESULT                               hr          = S_OK;

	IAppHostWritableAdminManager        * pWMgr       = NULL;
	IAppHostConfigManager               * pCfgMgr     = NULL;
	IAppHostConfigFile                  * pCfgFile    = NULL;
	IAppHostConfigLocationCollection * pLocations  = NULL;

	IAppHostElement *pAdminSection = NULL;
	IAppHostElementCollection *pElementCollection = NULL;
	IAppHostChildElementCollection *pChildElements = NULL;
	IAppHostElement *pElement = NULL;
	IAppHostElement *pNewElement = NULL;

	BSTR bstrConfigCommitPath = SysAllocString(L"MACHINE/WEBROOT/APPHOST/Default Web Site");
	BSTR bstrSectionName = SysAllocString(L"system.webServer/security/authentication/iisClientCertificateMappingAuthentication");
	BSTR bstrOneToOne = SysAllocString(L"oneToOneMappings");
	BSTR bstrElementName = SysAllocString(L"add");

	// Initialize
	hr = CoInitializeEx( NULL, COINIT_MULTITHREADED );

	// Create
	hr = CoCreateInstance( __uuidof( AppHostWritableAdminManager ), NULL,
		CLSCTX_INPROC_SERVER,
		__uuidof( IAppHostWritableAdminManager ), (void**) &pWMgr );

	pWMgr -> put_CommitPath ( bstrConfigCommitPath );

	hr = pWMgr->GetAdminSection(bstrSectionName, bstrConfigCommitPath, &pAdminSection);

	hr = pAdminSection->get_ChildElements(&pChildElements);

	PrintElementsOfCollection(pChildElements);

	hr = pAdminSection->GetElementByName(bstrOneToOne, &pElement);

	hr = pElement->get_Collection(&pElementCollection);

	//PrintElementsOfCollection(pElementCollection);

	hr = pElementCollection->CreateNewElement(bstrElementName, &pNewElement);

	//PrintPropertiesOfElement(pNewElement);

	hr = SetHostElementProperty(pNewElement, GenerateUserCertification());

        //got and error saying that another process is accesssing the data
	hr = pElementCollection->AddElement(pNewElement);  //got an error code 0x80070021 here |||||||||||||||||

	PrintElementsOfCollection(pElementCollection);

	// Commit the changes to the configuration system
	pWMgr->CommitChanges ( );
	return 0;
}