Add a CheckBox on CFileDialog (MFC cpp)

#include "afxdlgs.h"
class CDlgEventHandler : public CComObjectRootEx<CComSingleThreadModel>,
                         public CComCoClass<CDlgEventHandler>,
                         public IFileDialogEvents,
                         public IFileDialogControlEvents
{
public:
    CDlgEventHandler();
    ~CDlgEventHandler();

    BEGIN_COM_MAP(CDlgEventHandler)
        COM_INTERFACE_ENTRY(IFileDialogEvents)
        COM_INTERFACE_ENTRY(IFileDialogControlEvents)
    END_COM_MAP()

    // IFileDialogEvents
    STDMETHODIMP OnFileOk(IFileDialog* pfd);
    STDMETHODIMP OnFolderChanging(IFileDialog* pfd, IShellItem* psiFolder);
    STDMETHODIMP OnFolderChange(IFileDialog* pfd);
    STDMETHODIMP OnSelectionChange(IFileDialog* pfd);
    STDMETHODIMP OnShareViolation(IFileDialog* pfd, IShellItem* psi, FDE_SHAREVIOLATION_RESPONSE* pResponse);
    STDMETHODIMP OnTypeChange(IFileDialog* pfd);
    STDMETHODIMP OnOverwrite(IFileDialog* pfd, IShellItem* psi, FDE_OVERWRITE_RESPONSE* pResponse);

    // IFileDialogControlEvents
    STDMETHODIMP OnCheckButtonToggled(IFileDialogCustomize* pfdc, DWORD dwIDCtl, BOOL bChecked);
	STDMETHODIMP OnItemSelected(IFileDialogCustomize* pfdc, DWORD dwIDCtl, DWORD dwIDItem);
    STDMETHODIMP OnButtonClicked(IFileDialogCustomize* pfdc, DWORD dwIDCtl);
    STDMETHODIMP OnControlActivating(IFileDialogCustomize* pfdc, DWORD dwIDCtl);
};

// DlgEventHandler.h : interface of the CDlgEventHandler class

CDlgEventHandler::CDlgEventHandler()
{
}

CDlgEventHandler::~CDlgEventHandler()
{
}


/////////////////////////////////////////////////////////////////////////////
// IFileDialogEvents methods

STDMETHODIMP CDlgEventHandler::OnFileOk ( IFileDialog* pfd )
{
    return S_OK;    // allow the dialog to close
}

STDMETHODIMP CDlgEventHandler::OnFolderChanging ( IFileDialog* pfd, IShellItem* psiFolder )
{
    return S_OK;    // allow the change
}

STDMETHODIMP CDlgEventHandler::OnFolderChange ( IFileDialog* pfd )
{
    return S_OK;
}

STDMETHODIMP CDlgEventHandler::OnSelectionChange ( IFileDialog* pfd )
{
    return S_OK;
}

STDMETHODIMP CDlgEventHandler::OnShareViolation (
    IFileDialog* pfd, IShellItem* psi, FDE_SHAREVIOLATION_RESPONSE* pResponse )
{
    return S_OK;
}

STDMETHODIMP CDlgEventHandler::OnTypeChange ( IFileDialog* pfd )
{
    ATLTRACE(">> OnTypeChange\n");
    return S_OK;
}

STDMETHODIMP CDlgEventHandler::OnOverwrite (
    IFileDialog* pfd, IShellItem* psi, FDE_OVERWRITE_RESPONSE* pResponse )
{
    return S_OK;
}


/////////////////////////////////////////////////////////////////////////////
// IFileDialogControlEvents methods

STDMETHODIMP CDlgEventHandler::OnItemSelected (
    IFileDialogCustomize* pfdc, DWORD dwIDCtl, DWORD dwIDItem )
{ 
    return S_OK;
}

STDMETHODIMP CDlgEventHandler::OnButtonClicked (
    IFileDialogCustomize* pfdc, DWORD dwIDCtl )
{
    return S_OK;
}

STDMETHODIMP CDlgEventHandler::OnCheckButtonToggled (
    IFileDialogCustomize* pfdc, DWORD dwIDCtl, BOOL bChecked )
{

    ATLTRACE(">> OnCheckButtonToggled, button ID: %u, checked?: %d\n", dwIDCtl, bChecked);
    //dwIDCtl - ID of the checkbox clicked
    //Using pfdc we can control other events that we wanted to control on this click
    return S_OK;
}

STDMETHODIMP CDlgEventHandler::OnControlActivating (
    IFileDialogCustomize* pfdc, DWORD dwIDCtl )
{
    return S_OK;
}