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COSCHMOO
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IDROPTGT.CPP
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C/C++ Source or Header
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1993-05-18
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5KB
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263 lines
/*
* IDROPTGT.CPP
*
* Implementation of the DropTarget object.
*
* Copyright (c)1993 Microsoft Corporation, All Rights Reserved
*
* Kraig Brockschmidt, Software Design Engineer
* Microsoft Systems Developer Relations
*
* Internet : kraigb@microsoft.com
* Compuserve: >INTERNET:kraigb@microsoft.com
*/
#include "coschmoo.h"
/*
* CDropTarget::CDropTarget
* CDropTarget::~CDropTarget
*
* Constructor Parameters:
* pDoc LPCSchmooDoc of the document containing us.
*/
CDropTarget::CDropTarget(LPCSchmooDoc pDoc)
{
m_cRef=0;
m_pDoc=pDoc;
m_pIDataObject=NULL;
return;
}
CDropTarget::~CDropTarget(void)
{
return;
}
/*
* CDropTarget::QueryInterface
* CDropTarget::AddRef
* CDropTarget::Release
*
* Purpose:
* IUnknown members for CDropTarget object.
*/
STDMETHODIMP CDropTarget::QueryInterface(REFIID riid, LPVOID FAR *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 ResultFromScode(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
* we're interested in or not.
*
* Parameters:
* pIDataSource LPDATAOBJECT providing the source data.
* grfKeyState DWORD flags indicating 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:
* SCODE NOERROR
*/
STDMETHODIMP CDropTarget::DragEnter(LPDATAOBJECT pIDataSource
, DWORD grfKeyState, POINTL pt, LPDWORD pdwEffect)
{
HWND hWnd;
m_pIDataObject=NULL;
if (!m_pDoc->FQueryPasteFromData(pIDataSource))
{
*pdwEffect=DROPEFFECT_NONE;
return NOERROR;
}
*pdwEffect=DROPEFFECT_MOVE;
if (grfKeyState & MK_CONTROL)
*pdwEffect=DROPEFFECT_COPY;
m_pIDataObject=pIDataSource;
m_pIDataObject->AddRef();
hWnd=m_pDoc->Window();
BringWindowToTop(hWnd);
UpdateWindow(hWnd);
m_pDoc->DropSelectTargetWindow();
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:
* SCODE NOERROR
*/
STDMETHODIMP CDropTarget::DragOver(DWORD grfKeyState, POINTL pt
, LPDWORD pdwEffect)
{
if (NULL==m_pIDataObject)
{
*pdwEffect=DROPEFFECT_NONE;
return NOERROR;
}
*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:
* SCODE NOERROR
*/
STDMETHODIMP CDropTarget::DragLeave(void)
{
if (NULL==m_pIDataObject)
return NOERROR;
m_pDoc->DropSelectTargetWindow();
m_pIDataObject->Release();
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 do with the data.
*
* Return Value:
* SCODE NOERROR
*/
STDMETHODIMP CDropTarget::Drop(LPDATAOBJECT pIDataSource
, DWORD grfKeyState, POINTL pt, LPDWORD pdwEffect)
{
BOOL fRet=TRUE;
*pdwEffect=DROPEFFECT_NONE;
if (NULL==m_pIDataObject)
return ResultFromScode(E_FAIL);
m_pDoc->DropSelectTargetWindow();
m_pIDataObject->Release();
if (m_pDoc->m_fDragSource)
return ResultFromScode(E_FAIL);
fRet=m_pDoc->FPasteFromData(pIDataSource);
if (!fRet)
return ResultFromScode(E_FAIL);
*pdwEffect=DROPEFFECT_MOVE;
if (grfKeyState & MK_CONTROL)
*pdwEffect=DROPEFFECT_COPY;
return NOERROR;
}