The RichEdit control does not provide a direct method for
loading a bitmap and inserting it into an RTF document. The ActiveX control
(RichTextBox) provides the Add method through the COleObjects class, but this
action loads the bitmap for editing in the registered bitmap editor (usually
Paintbrush) before inserting it into the document. Both the DLL and the OCX
expose the IRichEditOle interface which, however, provides the InsertObject
method. This requires a fully-populated RichEdit Object (REOBJECT) structure to
be passed.
The following code is based on a project in which the
Microsoft RichText control has been inserted. With minor changes, it can apply
to the RichEdit DLL as well.
Create a new MFC dialog based application named RichText.
In the dialog editor, add a RichEdit control to the
application dialog resource. Use the code wizards to create a member variable,
m_ctlRichText, of type CRichEditCtrl, that is associated with the new RichEdit
control.
In the beginning of the InitInstance() method of the
CWinApp derived class of your project, add a call to AfxInitRichEdit() to
initialize the RichEdit common control.
Add four OLE interface pointers as member variables to the
CDialog derived class:
NOTE: Set these variables to NULL in your constructor. You must
include the header file Richole.h for the definition of the type
LPRICHEDITOLE.
Get the IRichEditOLE interface early on in your program (in
OnInitDialog or OnInitialUpdate) and keep it available. For the RichText
control, use the following method:
To insert the bitmap, create an embedded object from a
file. OLE provides the OleCreateFromFile function call to make this easier, but
you still need to prepare for the call. The following code is an amalgam of
techniques used within the MFC classes to provide similar functionality.
BOOL CRichTextDlg::CreateFromFile(LPCTSTR lpszFileName)
{
USES_CONVERSION;
ASSERT_VALID(this);
ASSERT(m_lpObject == NULL); // one time only
ASSERT(m_lpStorage == NULL);
ASSERT(m_lpClientSite == NULL);
LPLOCKBYTES lpLockBytes = NULL;
CLSID clsid = CLSID_NULL;
OLERENDER render = OLERENDER_DRAW;
CLIPFORMAT cfFormat = 0;
LPFORMATETC lpFormatEtc = NULL;
SCODE sc;
sc = ::CreateILockBytesOnHGlobal(NULL, TRUE, &lpLockBytes);
if (sc != S_OK)
AfxThrowOleException(sc);
ASSERT(lpLockBytes != NULL);
sc = ::StgCreateDocfileOnILockBytes(lpLockBytes,
STGM_SHARE_EXCLUSIVE|STGM_CREATE|STGM_READWRITE, 0, &m_lpStorage);
if (sc != S_OK)
{
VERIFY(lpLockBytes->Release() == 0);
lpLockBytes = NULL;
AfxThrowOleException(sc);
}
ASSERT(m_lpStorage != NULL);
// fill in FORMATETC struct
FORMATETC formatEtc;
lpFormatEtc = &formatEtc;
lpFormatEtc->cfFormat = cfFormat;
lpFormatEtc->ptd = NULL;
lpFormatEtc->dwAspect = DVASPECT_CONTENT;
lpFormatEtc->lindex = -1;
lpFormatEtc->tymed = TYMED_NULL;
// attempt to create the object
m_pRichEditOle->GetClientSite(&m_lpClientSite);
sc = ::OleCreateFromFile(clsid, T2COLE(lpszFileName),
IID_IUnknown, OLERENDER_DRAW, lpFormatEtc, m_lpClientSite, m_lpStorage,
(void**)&m_lpObject);
if (sc != S_OK)
AfxThrowOleException(sc);
// m_lpObject is currently an IUnknown, convert to IOleObject
if (m_lpObject != NULL)
{
LPUNKNOWN lpUnk = m_lpObject;
lpUnk->QueryInterface(IID_IOleObject, (void**)&m_lpObject);
lpUnk->Release();
if (m_lpObject == NULL)
AfxThrowOleException(E_OUTOFMEMORY);
}
// all items are "contained" -- this makes our reference to this object
// weak -- which is needed for links to embedding silent update.
OleSetContainedObject(m_lpObject, TRUE);
ASSERT_VALID(this);
return TRUE;
}
To use the function, simply pass the full path to a bitmap
as the file name parameter. The function creates a byte array in global memory
and a compound file storage object in that memory. It then populates the
FORMATETC structure, gets the client site, and creates the object within the
provided storage. The result is an IUnknown pointer to the object that is then
converted to a true IOleObject pointer by a call to QueryInterface.
Populate the RichEdit Object (REOBJECT) structure so it can
call InsertObject through the IRichEditOle pointer stored earlier. The
following code fills this structure:
At this point, make the InsertObject call. Insert the
bitmap at the bottom of the file. A combination of EM_GETSEL/EM_SETSEL messages
selects the document's text and positions the cursor at the end.
The bitmap is dropped neatly at the bottom of the document
with a carriage return separating it from the body of the text as in the
following code sample:
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