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idroptgt.cpp
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C/C++ Source or Header
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1996-05-21
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4KB
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187 lines
/*
* IDROPTGT.CPP
*
* Template implementation of a DropTarget object.
*
* Copyright (c)1993-1995 Microsoft Corporation, All Rights Reserved
*
* Kraig Brockschmidt, Microsoft
* 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;
if (IID_IUnknown==riid || IID_IDropTarget==riid)
*ppv=(LPVOID)this;
if (NULL!=*ppv)
{
((LPUNKNOWN)*ppv)->AddRef();
return NOERROR;
}
return ResultFromScode(E_NOINTERFACE);
}
STDMETHODIMP_(ULONG) CDropTarget::AddRef(void)
{
return ++m_cRef;
}
STDMETHODIMP_(ULONG) CDropTarget::Release(void)
{
if (0L!=--m_cRef)
return m_cRef;
delete this;
return 0;
}
/*
* 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.
*/
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.
*/
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
*/
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.
*/
STDMETHODIMP CDropTarget::Drop(LPDATAOBJECT pIDataSource
, DWORD grfKeyState, POINTL pt, LPDWORD pdwEffect)
{
return NOERROR;
}