컬렉션 - ATL

클라이언트는 루트 개체가 제공하는 읽기 전용의 속성을 통하여 컬렉션 개체에 접근하게 된다.


루트 개체

읽기 전용 속성의 컬렉션 개체를 노출

    interface ICompany : IDispatch
    {
        [propget, id(1), helpstring("property Employees")] HRESULT Employees([out, retval] VARIANT *pVal);
    };

컬렉션 개체

클래스 팩토리 관련 내용은 제거한다.

.Count
.Item[]
._NewEnum
[.Add()]
[.Remove()]

    interface IEmployees : IDispatch
    {
        [propget, id(1), helpstring("property Count")] HRESULT Count([out, retval] long *pVal);
        [propget, id(DISPID_VALUE), helpstring("property Item")] HRESULT Item([in] long index, [out, retval] VARIANT *pVal);
        [propget, id(DISPID_NEWENUM), helpstring("property _NewEnum")] HRESULT _NewEnum([out, retval] LPUNKNOWN *pVal);
    };

멤버 항목 개체

클래스 팩토리 관련 내용은 제거한다.

다른 컬렉션 개체를 제공할 수 있다.

    interface IEmployee : IDispatch
    {
        [propget, id(1), helpstring("property Name")] HRESULT Name([out, retval] BSTR *pVal);
        ...
    };

class ATL_NO_VTABLE CCompany :
    ...
    public IDispatchImpl<ICompany, &IID_ICompany, &LIBID_COMPANYLib>
{
// {
    CComObject<CEmployees>* m_pEmployees;
// }
public:
    CCompany()
    {
        m_pEmployees = new CComObject<CEmployees>;
        m_pEmployees->Init();
    }
...
BEGIN_COM_MAP(CCompany)
    COM_INTERFACE_ENTRY(ICompany)
    COM_INTERFACE_ENTRY(IDispatch)
    COM_INTERFACE_ENTRY(ISupportErrorInfo)
END_COM_MAP()

// ISupportsErrorInfo
    STDMETHOD(InterfaceSupportsErrorInfo)(REFIID riid);

// ICompany
public:
    STDMETHOD(get_Employees)(/*[out, retval]*/ VARIANT *pVal);
};


STDMETHODIMP CCompany::get_Employees(VARIANT *pVal)
{
    // TODO: Add your implementation code here
// {
    VariantInit(pVal);
    IDispatch* pDisp;
    m_pEmployees->QueryInterface(IID_IDispatch, (LPVOID*)&pDisp);
    pVal->vt = VT_DISPATCH;
    pVal->pdispVal = pDisp;
// }
    return S_OK;
}


class CEmployees :
    ...
    public CComObjectRoot
{
// {
    long m_Count;
    CComVariant* m_pEmployees;
// }
public:
// {
    void Init();
// }
    CEmployees() {
        m_pEmployees = NULL;
        m_Count = 0;
    }

    ~CEmployees() {
        delete [] m_pEmployees;
    }
BEGIN_COM_MAP(CEmployees)
    COM_INTERFACE_ENTRY(IDispatch)
    COM_INTERFACE_ENTRY(IEmployees)
    COM_INTERFACE_ENTRY(ISupportErrorInfo)
END_COM_MAP()
...
// IEmployees
public:
    STDMETHOD(get__NewEnum)(/*[out, retval]*/ LPUNKNOWN *pVal);
    STDMETHOD(get_Item)(/*[in]*/ long index, /*[out, retval]*/ VARIANT *pVal);
    STDMETHOD(get_Count)(/*[out, retval]*/ long *pVal);
};


void CEmployees::Init()
{
    ...
    if (m_pEmployees != NULL)
        delete [] m_pEmployees;
    m_Count = 10;
 
    m_pEmployees = new CComVariant[m_Count];
 
    CComObject<CEmployee>* pEmployee;
    LPDISPATCH lpDisp = NULL;
 
    for (int i = 0; i < m_Count; i++) {
        HRESULT hr = CComObject<CEmployee>::CreateInstance(&pEmployee);
        if(FAILED(hr)) {
            MessageBox(NULL, "Can't create Employe object", NULL, MB_OK);
            return;
        }
        pEmployee->m_Name = names[i];
        ...
        pEmployee->QueryInterface(IID_IDispatch, (void**)&lpDisp);
        CComVariant& var = m_pEmployees[i];
        var.vt = VT_DISPATCH;
        var.pdispVal = lpDisp;
    }
}

STDMETHODIMP CEmployees::get_Count(long *pVal)
{
    // TODO: Add your implementation code here
// {
    *pVal = m_Count;
// }
    return S_OK;
}

STDMETHODIMP CEmployees::get_Item(long index, VARIANT *pVal)
{
    // TODO: Add your implementation code here
// {
    if (NULL == pVal)
        return E_POINTER;
 
    // 인덱스는 1에서 시작(VB용)
    if ((index < 1) || (index > m_Count))
        return E_INVALIDARG;
   
    VariantInit(pVal);
    pVal->vt = VT_UNKNOWN;
    pVal->punkVal = NULL;
 
    // 0 에서 시작하는 인덱스로 변경
    HRESULT hr = VariantCopy(pVal, &m_pEmployees[index-1]);
    if(FAILED(hr))
        MessageBox(NULL, "Can't get the Item.", NULL, MB_OK);

    return hr;
// }
//    return S_OK;
}

STDMETHODIMP CEmployees::get__NewEnum(LPUNKNOWN *pVal)
{
    // TODO: Add your implementation code here
// {
    if (NULL == pVal)
        return E_POINTER;
    *pVal = NULL;
 
    typedef CComObject<
        CComEnum<IEnumVARIANT, &IID_IEnumVARIANT, VARIANT,
         _Copy<VARIANT> > > EnumVar;
    EnumVar* p = new EnumVar;
 
    HRESULT hr = p->Init(&m_pEmployees[0],
                         &m_pEmployees[m_Count],
                         NULL, AtlFlagCopy);
 
    if (SUCCEEDED(hr))
        hr = p->QueryInterface(IID_IEnumVARIANT, (LPVOID*)pVal);
    if (FAILED(hr))
        delete p;
 
    return hr;
// }
//    return S_OK;
}