如何在RichEdit中拖动对象？

Question

，比如在RichEdit中有Bmp、gif等对象，如何左右拖动

Answer 1

参考 CRichEditView  .

Answer 2

CRichEditOleCallback* m_pCallback;
         m_pCallback = new CRichEditOleCallback;
m_pCallback ->AddRef();
m_cRich.SetOLECallback(m_pCallback);RichEditOleCallback.h: interface for the CRichEditOleCallback class.
//
//////////////////////////////////////////////////////////////////////#if !defined(AFX_RICHEDITOLECALLBACK_H__F3691242_2C6E_4A88_A01C_F8C06D6641A5__INCLUDED_)
#define AFX_RICHEDITOLECALLBACK_H__F3691242_2C6E_4A88_A01C_F8C06D6641A5__INCLUDED_#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000#include <richole.h>
class CRichEditOleCallback : public IRichEditOleCallback  
{
protected:
ULONG m_cRef; // Object Reference Count
public:
CRichEditOleCallback();
virtual ~CRichEditOleCallback();
public: // IRichEditOleCallback Interface Members
STDMETHODIMP QueryInterface(REFIID riid, LPVOID* ppv);
STDMETHODIMP_(ULONG) AddRef(void);
STDMETHODIMP_(ULONG) Release(void); // IRichEditOleCallback Interface Members
STDMETHODIMP GetNewStorage(LPSTORAGE* ppStg);
STDMETHODIMP GetInPlaceContext(LPOLEINPLACEFRAME* ppFrame,
   LPOLEINPLACEUIWINDOW* ppDoc,
   LPOLEINPLACEFRAMEINFO pFrameInfo);
STDMETHODIMP ShowContainerUI(BOOL fShow);
STDMETHODIMP QueryInsertObject(LPCLSID pclsid, LPSTORAGE pStg, LONG cp);
STDMETHODIMP DeleteObject(LPOLEOBJECT pOleObj);
STDMETHODIMP QueryAcceptData(LPDATAOBJECT pDataObj, CLIPFORMAT* pcfFormat,
 DWORD reco, BOOL fReally, HGLOBAL hMetaPict);
STDMETHODIMP ContextSensitiveHelp(BOOL fEnterMode);
STDMETHODIMP GetClipboardData(CHARRANGE* pchrg, DWORD reco, 
  LPDATAOBJECT* ppDataObject);
STDMETHODIMP GetDragDropEffect(BOOL fDrag, DWORD grfKeyState,
   LPDWORD pdwEffect);
STDMETHODIMP GetContextMenu(WORD seltype, LPOLEOBJECT pOleObj,
    CHARRANGE* pchrg, HMENU* phMenu);
};#endif // !defined(AFX_RICHEDITOLECALLBACK_H__F3691242_2C6E_4A88_A01C_F8C06D6641A5__INCLU#include "stdafx.h"
#include <ole2.h>
#include <richedit.h>
#include "RichEditOleCallback.h"#ifdef _DEBUG
#undef THIS_FILE
static char THIS_FILE[]=__FILE__;
#define new DEBUG_NEW
#endifCRichEditOleCallback::CRichEditOleCallback()
{
m_cRef = 0;
}CRichEditOleCallback::~CRichEditOleCallback()
{}HRESULT CRichEditOleCallback::QueryInterface(REFIID riid, LPVOID* ppv)
{
    *ppv = NULL;

if (IID_IUnknown == riid)
{
*ppv = (LPUNKNOWN) this;
}
else if (IID_IRichEditOleCallback == riid)
{
*ppv = (LPRICHEDITOLECALLBACK)this;
} if (NULL == *ppv)
return ResultFromScode(E_NOINTERFACE); ((LPUNKNOWN) *ppv)->AddRef();
return NOERROR;
}ULONG CRichEditOleCallback::AddRef(void)
{
m_cRef++;
return m_cRef;
}ULONG CRichEditOleCallback::Release(void)
{
m_cRef--; if (0 == m_cRef)
delete this; return m_cRef;
}//关键是这里
HRESULT CRichEditOleCallback::GetNewStorage(LPSTORAGE* ppStg)
{
    if (!ppStg)
        return E_INVALIDARG;    *ppStg = NULL;    //
    // We need to create a new storage for an object to occupy.  We're going
    // to do this the easy way and just create a storage on an HGLOBAL and let
    // OLE do the management.  When it comes to saving things we'll just let
    // the RichEdit control do the work.  Keep in mind this is not efficient, 
    // but this program is just for demonstration.
    //    LPLOCKBYTES pLockBytes;
    HRESULT hr = CreateILockBytesOnHGlobal(NULL, TRUE, &pLockBytes);
    if (FAILED(hr))
        return hr;    hr = StgCreateDocfileOnILockBytes(pLockBytes, 
                                      STGM_SHARE_EXCLUSIVE | STGM_CREATE |
                                          STGM_READWRITE,
                                      0,
                                      ppStg);
    pLockBytes->Release();
    return (hr);
}HRESULT CRichEditOleCallback::GetInPlaceContext(LPOLEINPLACEFRAME*,
LPOLEINPLACEUIWINDOW*, LPOLEINPLACEFRAMEINFO)
{
return S_OK;
}HRESULT CRichEditOleCallback::ShowContainerUI(BOOL)
{ return S_OK;
}HRESULT CRichEditOleCallback::QueryInsertObject(LPCLSID /* pclsid */,
LPSTORAGE /* pStg */,
LONG /* cp */)
{
return S_OK;
}HRESULT CRichEditOleCallback::DeleteObject(LPOLEOBJECT pOleObj)
{
return S_OK;
}
HRESULT CRichEditOleCallback::QueryAcceptData(LPDATAOBJECT, CLIPFORMAT*,
  DWORD, BOOL, HGLOBAL)
{
return S_OK;
}HRESULT CRichEditOleCallback::ContextSensitiveHelp(BOOL)
{
return E_NOTIMPL;
}HRESULT CRichEditOleCallback::GetClipboardData(CHARRANGE*, DWORD, LPDATAOBJECT*){
return E_NOTIMPL;
}HRESULT CRichEditOleCallback::GetDragDropEffect(BOOL /* fDrag */,
DWORD /* grfKeyState */,
LPDWORD /* pdwEffect */)
{
return E_NOTIMPL;
}HRESULT CRichEditOleCallback::GetContextMenu(WORD,
 LPOLEOBJECT,
 CHARRANGE*,
 HMENU*)
{
return S_OK;
}