IDROPTGT.CPP

/* 
 * IDROPTGT.CPP 
 * 
 * Template implementation of a DropTarget object. 
 * 
 * Copyright (c)1993-1996 Microsoft Corporation, All Rights Reserved 
 * 
 * Kraig Brockschmidt, Software Design Engineer 
 * Microsoft Systems Developer Relations 
 * 
 * Internet  :  kraigb@microsoft.com 
 * Compuserve:  >INTERNET:kraigb@microsoft.com 
 */ 
 
 
#include "idroptgt.h" 
 
 
 
/* 
 * CDropTarget::CDropTarget 
 * CDropTarget::~CDropTarget 
 * 
 * Constructor Parameters: 
 *  pBack           LPVOID back pointer to whatever we're related to. 
 */ 
 
CDropTarget::CDropTarget(LPVOID pBack) 
    { 
    m_cRef=0; 
    m_pBack=pBack; 
    return; 
    } 
 
 
CDropTarget::~CDropTarget(void) 
    { 
    return; 
    } 
 
 
 
 
/* 
 * CDropTarget::QueryInterface 
 * CDropTarget::AddRef 
 * CDropTarget::Release 
 * 
 * Purpose: 
 *  Non-delegating IUnknown members for CDropTarget. 
 */ 
 
STDMETHODIMP CDropTarget::QueryInterface(REFIID riid 
    , LPVOID *ppv) 
    { 
    *ppv=NULL; 
 
    //Any interface on this object is the object pointer. 
    if (IsEqualIID(riid, IID_IUnknown) 
        || IsEqualIID(riid, IID_IDropTarget)) 
        *ppv=(LPVOID)this; 
 
    /* 
     * If we actually assign an interface to ppv we need to AddRef 
     * it since we're returning a new pointer. 
     */ 
    if (NULL!=*ppv) 
        { 
        ((LPUNKNOWN)*ppv)->AddRef(); 
        return NOERROR; 
        } 
 
    return E_NOINTERFACE; 
    } 
 
 
STDMETHODIMP_(ULONG) CDropTarget::AddRef(void) 
    { 
    return ++m_cRef; 
    } 
 
STDMETHODIMP_(ULONG) CDropTarget::Release(void) 
    { 
    ULONG   cRefT; 
 
    cRefT=--m_cRef; 
 
    if (0L==m_cRef) 
        delete this; 
 
    return cRefT; 
    } 
 
 
 
 
 
 
/* 
 * CDropTarget::DragEnter 
 * 
 * Purpose: 
 *  Indicates that data in a drag operation has been dragged over 
 *  our window that's a potential target.  We are to decide if it's 
 *  something in which we're interested. 
 * 
 * Parameters: 
 *  pIDataSource    LPDATAOBJECT providing the source data. 
 *  grfKeyState     DWORD flags: states of keys and mouse buttons. 
 *  pt              POINTL coordinates in the client space of 
 *                  the document. 
 *  pdwEffect       LPDWORD into which we'll place the appropriate 
 *                  effect flag for this point. 
 * 
 * Return Value: 
 *  HRESULT         NOERROR 
 */ 
 
STDMETHODIMP CDropTarget::DragEnter(LPDATAOBJECT pIDataSource 
    , DWORD grfKeyState, POINTL pt, LPDWORD pdwEffect) 
    { 
    *pdwEffect=DROPEFFECT_NONE; 
    return NOERROR; 
    } 
 
 
 
 
 
 
/* 
 * CDropTarget::DragOver 
 * 
 * Purpose: 
 *  Indicates that the mouse was moved inside the window represented 
 *  by this drop target.  This happens on every WM_MOUSEMOVE, so 
 *  this function should be very efficient. 
 * 
 * Parameters: 
 *  grfKeyState     DWORD providing the current keyboard and 
 *                  mouse states 
 *  pt              POINTL where the mouse currently is. 
 *  pdwEffect       LPDWORD in which to store the effect flag 
 *                  for this point. 
 * 
 * Return Value: 
 *  HRESULT         NOERROR 
 */ 
 
STDMETHODIMP CDropTarget::DragOver(DWORD grfKeyState, POINTL pt 
    , LPDWORD pdwEffect) 
    { 
    //Since we can always drop, we just return effect flags 
    *pdwEffect=DROPEFFECT_MOVE; 
 
    if (grfKeyState & MK_CONTROL) 
        *pdwEffect=DROPEFFECT_COPY; 
 
    return NOERROR; 
    } 
 
 
 
 
 
 
/* 
 * CDropTarget::DragLeave 
 * 
 * Purpose: 
 *  Informs the drop target that the operation has left its window. 
 * 
 * Parameters: 
 *  None 
 * 
 * Return Value: 
 *  HRESULT         NOERROR 
 */ 
 
STDMETHODIMP CDropTarget::DragLeave(void) 
    { 
    return NOERROR; 
    } 
 
 
 
 
 
/* 
 * CDropTarget::Drop 
 * 
 * Purpose: 
 *  Instructs the drop target to paste the data that was just now 
 *  dropped on it. 
 * 
 * Parameters: 
 *  pIDataSource    LPDATAOBJECT from which we'll paste. 
 *  grfKeyState     DWORD providing current keyboard/mouse state. 
 *  pt              POINTL at which the drop occurred. 
 *  pdwEffect       LPDWORD in which to store what you did. 
 * 
 * Return Value: 
 *  HRESULT         NOERROR 
 */ 
 
STDMETHODIMP CDropTarget::Drop(LPDATAOBJECT pIDataSource 
    , DWORD grfKeyState, POINTL pt, LPDWORD pdwEffect) 
    { 
    return NOERROR; 
    }