Wrong handle while setting text to RichEdit control-CodePudding

I can set plain text to RichEdit control with SF_TEXT flag, but I cann't set RTF-text with SF_RTF flag.

Here is the creation of control:

    LoadLibrary(TEXT("Riched20.dll"));

    richEdit = CreateWindowEx(
        0,
        RICHEDIT_CLASS,
        TEXT(""),
        ES_MULTILINE | WS_VISIBLE | WS_CHILD | WS_BORDER | WS_TABSTOP,
        x,
        y,
        width,
        height,
        hwndOwner,
        NULL,
        hInstance,
        NULL);
}

And here is how I set text (I took example somewhere in SO), resulting in "ERROR_INVALID_HANDLE":

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

    // ......
    // Setting text
    std::wstringstream rtf(L"{\rtf1Hello!\par{ \i This } is some { \b text }.\par}");
    EDITSTREAM es = { 0 };
    es.dwCookie = (DWORD_PTR)&rtf;
    es.pfnCallback = &EditStreamInCallback;

    if (SendMessage(richEdit, EM_STREAMIN, SF_RTF, (LPARAM)&es) && es.dwError == 0)
    {
        // ...
    } else {
        auto error = GetLastError(); // error == 6
    }

CodePudding user response：

RTF string should be "\\r \\p" etc. not "\r \p", or use raw string literal. The string should have compatible font. For example:

std::wstring wrtf = (LR"({\rtf1{\fonttbl\f0\fswiss Helvetica;} 
Hello world Привет Ελληνικά 日本語 { \b bold \b } regular.\par})");

EM_STREAMIN/EM_STREAMOUT expect BYTE input/output.

When reading/writing standard RTF file, just read the file as char, don't do any conversion to wide string, and use this format

format = SF_RTF;

If source is UTF16 string literal, convert it to UTF8, everything else stays the same, except format changes to:

format = SF_RTF | SF_USECODEPAGE | (CP_UTF8 << 16);

Example reading UTF16 string literal in to RichEdit control:

std::string utf8(const std::wstring& wstr)
{
    if (wstr.empty()) return std::string();
    int sz = WideCharToMultiByte(CP_UTF8,0,wstr.c_str(),-1,0,0,0,0);
    std::string res(sz, 0);
    WideCharToMultiByte(CP_UTF8,0,wstr.c_str(),(int)wstr.size(),&res[0],sz,0,0);
    return res;
}

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 ss(utf8(wrtf));
EDITSTREAM es = { 0 };
es.dwCookie = (DWORD_PTR)&ss;
es.pfnCallback = &EditStreamInCallback;
SendMessage(richedit, EM_STREAMIN, 
    SF_RTF | SF_USECODEPAGE | (CP_UTF8 << 16), (LPARAM)&es);