How to get text with RTF format from Rich Edit Win API?

Question

(Sorry for my crazy English) I want to get all the text in Rich Edit with RTF format, not plain text to a variable. I tried SendMessage() with EM_STREAMOUT to write directly

Answer 1

You can pass your variable to the EM_STREAMOUT callback so it can be updated as needed, eg:

DWORD CALLBACK EditStreamOutCallback(DWORD_PTR dwCookie, LPBYTE pbBuff, LONG cb, LONG *pcb)
{
    std::stringstream *rtf = (std::stringstream*) dwCookie;
    rtf->write((char*)pbBuff, cb);
    *pcb = cb;
    return 0;
}

.

std::stringstream rtf;

EDITSTREAM es = {0};
es.dwCookie = (DWORD_PTR) &rtf;
es.pfnCallback = &EditStreamOutCallback; 
SendMessage(hRichEditWnd, EM_STREAMOUT, SF_RTF, (LPARAM)&es);

// use rtf.str() as needed...

Update: to load RTF data into the RichEdit control, use EM_STREAMIN, eg:

DWORD CALLBACK EditStreamInCallback(DWORD_PTR dwCookie, LPBYTE pbBuff, LONG cb, LONG *pcb)
{
    std::stringstream *rtf = (std::stringstream*) dwCookie;
    *pcb = rtf->readsome((char*)pbBuff, cb);
    return 0;
}

.

std::stringstream rtf("...");

EDITSTREAM es = {0};
es.dwCookie = (DWORD_PTR) &rtf;
es.pfnCallback = &EditStreamInCallback; 
SendMessage(hRichEditWnd, EM_STREAMIN, SF_RTF, (LPARAM)&es);

Answer 2

Using the EM_STREAMOUT message is the answer.

Here is the simplest example that I can construct to demonstrate. This will save the contents of a rich edit control to a file.

DWORD CALLBACK EditStreamOutCallback(DWORD_PTR dwCookie, LPBYTE pbBuff, LONG cb, LONG *pcb)
{
    HANDLE hFile = (HANDLE)dwCookie;
    DWORD NumberOfBytesWritten;
    if (!WriteFile(hFile, pbBuff, cb, &NumberOfBytesWritten, NULL))
    {
        //handle errors
        return 1;
        // or perhaps return GetLastError();
    }
    *pcb = NumberOfBytesWritten;
    return 0;
}

void SaveRichTextToFile(HWND hWnd, LPCWSTR filename)
{
    HANDLE hFile = CreateFile(filename, GENERIC_WRITE, 0, NULL,
        CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
    if (hFile == INVALID_HANDLE_VALUE)
    {
        //handle errors
    }
    EDITSTREAM es = { 0 };
    es.dwCookie = (DWORD_PTR) hFile;
    es.pfnCallback = EditStreamOutCallback; 
    SendMessage(hWnd, EM_STREAMOUT, SF_RTF, (LPARAM)&es);
    CloseHandle(hFile);
    if (es.dwError != 0)
    {
        //handle errors
    }
}