COM

interface ITreeItem : IDispatch
{
	HRESULT AddChild(void);
	HRESULT GetChildCount([out,retval] LONG* pChildCount);
};
interface IExtensionInfo : IUnknown
{
	HRESULT GetCaption([out, retval] BSTR* caption);
	HRESULT SetCaption([in] BSTR caption);
	HRESULT Init([in] ITreeItem* ipTreeItem);
	HRESULT Unload(void);
};

LRESULT CMainWindow::OnCreate(UINT uMsg, WPARAM wParam, LPARAM lParam, BOOL& bHandled)
{
	HRESULT hr;
	_AtlModule.Lock();
	
	this->m_pCtrlWindow = new CAxWindow();
	// Get rect of visible area.
	RECT rect;
	this->GetClientRect(&rect);
	// Create control window.
	HWND hControlWindow = this->m_pCtrlWindow->Create(this->m_hWnd, rect, NULL, WS_CHILD | WS_VISIBLE);
	
	IUnknown *pUnknownControl;
	// Load the control via the ProgID.
	hr = this->m_pCtrlWindow->CreateControlEx(L"CsControlInNativeWindow.Extension", NULL, NULL, &pUnknownControl);
	this->m_spExtensionInfo = pUnknownControl;
	if (pUnknownControl)
	{
		pUnknownControl->Release();
	}
	
	// Create a TreeItem COM object which the Extension can access.
	this->m_spTreeItem.CoCreateInstance(CLSID_TreeItem);
	this->m_spExtensionInfo->Init(this->m_spTreeItem);
	
	return 0;
}

LRESULT CMainWindow::OnDestroy(UINT uMsg, WPARAM wParam, LPARAM lParam, BOOL& bHandled)
{
	if (this->m_spTreeItem)
	{
		this->m_spTreeItem.Release();
	}
	
	if (this->m_spExtensionInfo)
	{
// Inform the control that we do not need it anymore.
		this->m_spExtensionInfo->Unload();
		this->m_spExtensionInfo.Release();
	}

	if (this->m_pCtrlWindow)
	{
		this->m_pCtrlWindow->DestroyWindow();
		delete this->m_pCtrlWindow;
		this->m_pCtrlWindow = NULL;
	}
	
	_AtlModule.Unlock();
	return 0;
}