ENUM.CPP

/************************************************************************* 
** 
**  This is a part of the Microsoft Source Code Samples. 
** 
**  Copyright 1992 - 1998 Microsoft Corporation. All rights reserved. 
** 
**  This source code is only intended as a supplement to Microsoft Development 
**  Tools and/or WinHelp documentation.  See these sources for detailed 
**  information regarding the Microsoft samples programs. 
** 
**  OLE Automation TypeLibrary Browse Helper Sample 
** 
**  enum.cpp 
** 
**  CEnum implementation 
** 
**  Written by Microsoft Product Support Services, Windows Developer Support 
** 
*************************************************************************/ 
 
#include <windows.h> 
#include <windowsx.h> 
#ifdef WIN16    
  #include <ole2.h> 
  #include <compobj.h>     
  #include <dispatch.h>  
  #include <variant.h> 
  #include <olenls.h>   
#endif  
#include "browseh.h"   
 
/* 
 * CEnum::Create 
 * 
 * Purpose: 
 *  Creates an instance of the Enum automation object and initializes it. 
 * 
 * Parameters:        
 *  ptinfo    TypeInfo of Enum. 
 *  ppEnum    Returns Enum automation object. 
 * 
 * Return Value: 
 *  HRESULT 
 * 
 */ 
HRESULT  
CEnum::Create(LPTYPEINFO ptinfo, CEnum FAR* FAR* ppEnum)  
{    
    HRESULT hr; 
    CEnum FAR* pEnum = NULL; 
      
    *ppEnum = NULL; 
     
    // Create object. 
    pEnum = new CEnum(); 
    if (pEnum == NULL) 
    { 
        hr = E_OUTOFMEMORY;  
        goto error; 
    }    
    // Load type information for the object from type library.  
    hr = pEnum->LoadTypeInfo(IID_IEnum); 
    if (FAILED(hr)) 
        goto error;   
    // Ask base class (CTypeInfo) to initialize.         
    hr = pEnum->_InitTypeInfo(ptinfo); 
    if (FAILED(hr)) 
        goto error; 
     
    ptinfo->AddRef(); 
    pEnum->m_ptinfo = ptinfo; 
 
#ifdef _DEBUG   
    lstrcpyn(pEnum->m_szClassName, TEXT("Enum"), 100); 
#endif 
         
    *ppEnum = pEnum; 
    return NOERROR; 
     
error: 
    if (pEnum == NULL) return E_OUTOFMEMORY; 
    if (pEnum->m_ptinfo) pEnum->m_ptinfo->Release(); 
          
    // Set to NULL to prevent destructor from attempting to free again   
    pEnum->m_ptinfo = NULL; 
     
    delete pEnum; 
    return hr; 
} 
 
/* 
 * CEnum::CEnum 
 * 
 * Purpose: 
 *  Constructor for CEnum object. Initializes members to NULL. 
 * 
 */ 
CEnum::CEnum() 
{ 
    m_pdispElements = NULL;       
    m_ptinfo = NULL; 
} 
 
/* 
 * CEnum::~CEnum 
 * 
 * Purpose: 
 *  Destructor for CEnum object.  
 * 
 */ 
CEnum::~CEnum() 
{ 
    if (m_pdispElements) m_pdispElements->Release(); 
    if (m_ptinfo) m_ptinfo->Release(); 
}   
 
STDMETHODIMP_(REFCLSID) 
CEnum::GetInterfaceID() 
{ 
    return IID_IEnum; 
} 
 
STDMETHODIMP_(ICollection FAR*) 
CEnum::get_Elements()      
{     
    HRESULT hr; 
    CConstant FAR* pConstant; 
    CCollection FAR* pCollection = NULL; 
    LPDISPATCH pdisp; 
    LPVARDESC pvardesc = NULL;    
    LPTYPEATTR ptypeattr = NULL; 
    unsigned short n; 
     
    if (m_pdispElements == NULL) 
    {     
        hr = m_ptinfo->GetTypeAttr(&ptypeattr); 
        if (FAILED(hr)) 
            {RaiseException(IDS_Unexpected); return NULL;}        
        hr = CCollection::Create(ptypeattr->cVars, 0, &pCollection);   
        if (FAILED(hr)) 
            {RaiseException(IDS_Unexpected); goto error;}      
        // Enumerate enum constants and return a collection of these. 
        for (n=0; n<ptypeattr->cVars; n++) 
        {        
            hr = m_ptinfo->GetVarDesc(n, &pvardesc);    
            if (FAILED(hr)) 
                {RaiseException(IDS_Unexpected); goto error;}    
            hr = CConstant::Create(m_ptinfo, pvardesc, &pConstant); 
            if (FAILED(hr)) 
                {RaiseException(IDS_Unexpected); goto error;}     
            m_ptinfo->ReleaseVarDesc(pvardesc);  
            pvardesc = NULL; 
            pConstant->QueryInterface(IID_IDispatch, (void FAR* FAR*)&pdisp); 
            pCollection->Add(pdisp);    
            pdisp->Release(); 
        } 
        pCollection->QueryInterface(IID_IDispatch, (void FAR* FAR*)&pdisp); 
        m_pdispElements = pdisp;     
        m_ptinfo->ReleaseTypeAttr(ptypeattr);  
    } 
    m_pdispElements->AddRef(); 
    return (ICollection FAR*)m_pdispElements; 
 
error:   
    if (ptypeattr) m_ptinfo->ReleaseTypeAttr(ptypeattr);    
    if (pCollection) delete pCollection;    
    if (pvardesc) m_ptinfo->ReleaseVarDesc(pvardesc);    
    return NULL; 
}