DATAOBJ.CPP

/* 
 * DATAOBJ.CPP 
 * Data Transfer Object Chapter 12 
 * 
 * Implementation of the CDataObject class. 
 * 
 * Copyright (c)1993-1995 Microsoft Corporation, All Rights Reserved 
 * 
 * Kraig Brockschmidt, Microsoft 
 * Internet  :  kraigb@microsoft.com 
 * Compuserve:  >INTERNET:kraigb@microsoft.com 
 */ 
 
 
#include "dataobj.h" 
 
extern HINSTANCE g_hInst; 
 
/* 
 * CDataObject::CDataObject 
 * CDataObject::~CDataObject 
 * 
 * Parameters (Constructor): 
 *  pUnkOuter       LPUNKNOWN of a controlling unknown. 
 *  pfnDestroy      PFNDESTROYED to call when object is destroyed. 
 */ 
 
CDataObject::CDataObject(LPUNKNOWN pUnkOuter 
    , PFNDESTROYED pfnDestroy) 
    { 
    m_cRef=0; 
    m_pUnkOuter=pUnkOuter; 
    m_pfnDestroy=pfnDestroy; 
 
    m_hList=NULL; 
    m_pIDataObject=NULL; 
 
    return; 
    } 
 
 
CDataObject::~CDataObject(void) 
    { 
    if (NULL!=m_pIDataObject) 
        delete m_pIDataObject; 
 
    Purge(); 
 
    if (NULL!=m_hList) 
        DestroyWindow(m_hList); 
 
    return; 
    } 
 
 
 
/* 
 * CDataObject::Init 
 * 
 * Purpose: 
 *  Performs any intiailization of a CDataObject that's prone to 
 *  failure that we also use internally before exposing the object 
 *  outside. 
 * 
 * Parameters: 
 *  None 
 * 
 * Return Value: 
 *  BOOL            TRUE if the function is successful, 
 *                  FALSE otherwise. 
 */ 
 
BOOL CDataObject::Init(void) 
    { 
    LPUNKNOWN       pIUnknown=this; 
 
    if (NULL!=m_pUnkOuter) 
        pIUnknown=m_pUnkOuter; 
 
    //Allocate contained interfaces. 
    m_pIDataObject=new CImpIDataObject(this, pIUnknown); 
 
    if (NULL==m_pIDataObject) 
        return FALSE; 
 
    m_hList=CreateWindow(TEXT("listbox"), TEXT("renderings") 
        , WS_POPUP | LBS_OWNERDRAWFIXED, 0, 0, 100, 100 
        , HWND_DESKTOP, NULL, g_hInst, NULL); 
 
    if (NULL==m_hList) 
        return FALSE; 
 
    return TRUE; 
    } 
 
 
 
/* 
 * CDataObject::Purge 
 * 
 * Purpose: 
 *  Cleans out all entries in our listbox. 
 * 
 * Parameters: 
 *  None 
 * 
 * Return Value: 
 *  None 
 */ 
 
void CDataObject::Purge(void) 
    { 
    UINT        i, cItems; 
    PRENDERING  pRen; 
    DWORD       cb; 
 
    if (NULL==m_hList) 
        return; 
 
    cItems=(UINT)SendMessage(m_hList, LB_GETCOUNT, 0, 0L); 
 
    for (i=0; i < cItems; i++) 
        { 
        cb=SendMessage(m_hList, LB_GETTEXT, i, (LPARAM)&pRen); 
 
        if (LB_ERR!=cb) 
            { 
            /* 
             * Release the data completely being sure to reinstate 
             * the original pUnkForRelease. 
             */ 
            pRen->stm.pUnkForRelease=pRen->pUnkOrg; 
            ReleaseStgMedium(&pRen->stm); 
            delete pRen; 
            } 
        } 
 
    SendMessage(m_hList, LB_RESETCONTENT, 0, 0L); 
    return; 
    } 
 
 
 
 
 
 
/* 
 * CDataObject::QueryInterface 
 * CDataObject::AddRef 
 * CDataObject::Release 
 * 
 * Purpose: 
 *  IUnknown members for CDataObject object. 
 */ 
 
STDMETHODIMP CDataObject::QueryInterface(REFIID riid, PPVOID ppv) 
    { 
    *ppv=NULL; 
 
    if (IID_IUnknown==riid) 
        *ppv=this; 
 
    if (IID_IDataObject==riid) 
        *ppv=m_pIDataObject; 
 
    if (NULL!=*ppv) 
        { 
        ((LPUNKNOWN)*ppv)->AddRef(); 
        return NOERROR; 
        } 
 
    return ResultFromScode(E_NOINTERFACE); 
    } 
 
 
STDMETHODIMP_(ULONG) CDataObject::AddRef(void) 
    { 
    return ++m_cRef; 
    } 
 
 
STDMETHODIMP_(ULONG) CDataObject::Release(void) 
    { 
    if (0!=--m_cRef) 
        return m_cRef; 
 
    if (NULL!=m_pfnDestroy) 
        (*m_pfnDestroy)(); 
 
    delete this; 
    return 0; 
    }