I am trying to get the text of the currently chosen tab in CTabCtrl.
int tabCurSel = currentTabCtrl->GetCurSel();
TCITEM tcItem;
tcItem.mask = TCIF_TEXT;
tcItem.cchTextMax = 256; //Do I need this?
CString tabCurrentCString;
currentTabCtrl->GetItem(tabCurSel, &tcItem);
tabCurrentCString = tcItem.pszText;
CT2A tabCurrentChar(tabCurrentCString);
std::string tabCurrentStr(tabCurrentChar);
return tabCurrentStr;
I clearly have some unnecessary string conversions and currently this returns a "Error reading characters of the string" in
tcItem.pszText;
How can I get the string from the CTabCtrl? I ultimately am trying to get an std::string but the main question is how to get the text from the tab.
tcItem.pszText is pointing to 0. To fill it with text, it has to point to a buffer before a call is made to GetItem:
Documentation for: CTabCtrl::GetItem
pszText
Pointer to a null-terminated string containing the tab text if the
structure contains information about a tab. If the structure is
receiving information, this member specifies the address of the buffer
that receives the tab text.
Example:
TCITEM tcItem { 0 };
tcItem.mask = TCIF_TEXT;
const int len = 256;
tcItem.cchTextMax = len;
TCHAR buf[len] = { 0 };
tcItem.pszText = buf;
currentTabCtrl->GetItem(tabCurSel, &tcItem);
Both tcItem.pszText and buf will point to the same text. Or use CString with CString::GetBuffer()/CString::ReleaseBuffer()
CString tabCurrentCString;
TCITEM tcItem;
tcItem.mask = TCIF_TEXT;
tcItem.cchTextMax = 256;
tcItem.pszText = tabCurrentCString.GetBuffer(tcItem.cchTextMax);
BOOL result = currentTabCtrl->GetItem(tabCurSel, &tcItem);
tabCurrentCString.ReleaseBuffer();
if (result)
MessageBox(tabCurrentCString); //success
It looks like you are using the recommended Unicode settings. Avoid converting UNICODE to ANSI (std::string). This conversion will work for Latin languages, most of the time, but it's not needed. You can use std::wstring if you need to use that in STL, or convert to UTF-8 if you want to send data to internet etc.
std::string str = CW2A(tabCurrentCString, CP_UTF8);
I am using following piece of code for converting to UTF 8 on Linux. Please note that for me sizeof(wchar_t) = 2 due to compiler flag
void convert(const wchar_t* data, size_t len)
{
ASSERT(sizeof(wchar_t) == sizeof(jchar));
JNIEnv* env = GetEnv();
JString jstr = env->NewString((const jchar *)data, len);
int cbMLen = jStr.GetStringUTFLength();
char* pUTF8Str = new (std::nothrow) char[cbLen + 1];
//IFALLOCFAILED_EXIT(pUTF8String);
strncpy_s(pUTF8Str, cbLen + 1, jStr.GetUTFString(), cbLen);
// release memory...
}
Code is crashing at NewString for certain set of Unicode characters. Am I doing something wrong?
I'm writing an MFC app with C++ in Visual Studio 2012. App connects to a MySQL database and shows every row to a List Box.
Words are in Russian, database encoding is cp1251. I've set the same character set using this code:
if (!mysql_set_character_set(mysql, "cp1251")) {
statusBox.SetWindowText((CString)"CP1251 is set for MYSQL.");
}
But it doesn't help at all.
I display data using this code:
while ((row = mysql_fetch_row(result)) != NULL) {
CString string = (CString)row[1];
listBox.AddString(string);
}
This code also doesn't help:
mysql_query(mysql, "set names cp1251");
Please help. What should I do to display cyrillic correctly?
When crossing system boundaries that use different character encodings you have to convert between them. In this case, the MySQL database uses CP 1251 while Windows (and CString) use UTF-16. The conversion might look like this:
#if !defined(_UNICODE)
#error Unicode configuration required
#endif
CString CPtoUnicode( const char* CPString, UINT CodePage ) {
CString retValue;
// Retrieve required string length
int len = MultiByteToWideChar( CodePage, 0,
CPString, -1,
NULL, 0 );
if ( len == 0 ) {
// Error -> return empty string
return retValue;
}
// Allocate CString's internal buffer
LPWSTR buffer = retValue.GetBuffer( len );
// Do the conversion
MultiByteToWideChar( CodePage, 0,
CPString, -1,
buffer, len );
// Return control of the buffer back to the CString object
retValue.ReleaseBuffer();
return retValue;
}
This should be used as follows:
while ( ( row = mysql_fetch_row( result ) ) != NULL ) {
CString string = CPtoUnicode( row[1], 1251 );
listBox.AddString( string );
}
Alternatively, you could use CStrings built-in conversion support, which requires to set the thread's locale to the source encoding (CP 1251) and use the conversion constructor.
My question is nearly identical to this question, except that the linked question deals with char*, whereas I'm using std::string in my code. Like the linked question, I'm also using C# as my target language.
I have a class written in C++:
class MyClass
{
public:
const std::string get_value() const; // returns utf8-string
void set_value(const std::string &value); // sets utf8-string
private:
// ...
};
And this get's wrapped by SWIG in C# as follows:
public class MyClass
{
public string get_value();
public void set_value(string value);
}
SWIG does everything for me, except that it doesn't make an utf8 to utf16 string conversion during the calls to MyClass. My strings come through fine if they are representable in ASCII, but if I try passing a string with non-ascii characters in a round-trip through "set_value" and "get_value", I end up with unintelligible characters.
How can I make SWIG wrap UTF-8 encoded C++ strings in C#? n.b. I'm using std::string, not std::wstring, and not char*.
There's a partial solution on the SWIG sourceforge site, but it deals with char* not std::string, and it uses a (configurable) fixed length buffer.
With the help (read: genius!) of David Jeske in the linked Code Project article, I have finally been able to answer this question.
You'll need this class (from David Jeske's code) in your C# library.
public class UTF8Marshaler : ICustomMarshaler {
static UTF8Marshaler static_instance;
public IntPtr MarshalManagedToNative(object managedObj) {
if (managedObj == null)
return IntPtr.Zero;
if (!(managedObj is string))
throw new MarshalDirectiveException(
"UTF8Marshaler must be used on a string.");
// not null terminated
byte[] strbuf = Encoding.UTF8.GetBytes((string)managedObj);
IntPtr buffer = Marshal.AllocHGlobal(strbuf.Length + 1);
Marshal.Copy(strbuf, 0, buffer, strbuf.Length);
// write the terminating null
Marshal.WriteByte(buffer + strbuf.Length, 0);
return buffer;
}
public unsafe object MarshalNativeToManaged(IntPtr pNativeData) {
byte* walk = (byte*)pNativeData;
// find the end of the string
while (*walk != 0) {
walk++;
}
int length = (int)(walk - (byte*)pNativeData);
// should not be null terminated
byte[] strbuf = new byte[length];
// skip the trailing null
Marshal.Copy((IntPtr)pNativeData, strbuf, 0, length);
string data = Encoding.UTF8.GetString(strbuf);
return data;
}
public void CleanUpNativeData(IntPtr pNativeData) {
Marshal.FreeHGlobal(pNativeData);
}
public void CleanUpManagedData(object managedObj) {
}
public int GetNativeDataSize() {
return -1;
}
public static ICustomMarshaler GetInstance(string cookie) {
if (static_instance == null) {
return static_instance = new UTF8Marshaler();
}
return static_instance;
}
}
Then, in Swig's "std_string.i", on line 24 replace this line:
%typemap(imtype) string "string"
with this line:
%typemap(imtype, inattributes="[MarshalAs(UnmanagedType.CustomMarshaler, MarshalTypeRef = typeof(UTF8Marshaler))]", outattributes="[return: MarshalAs(UnmanagedType.CustomMarshaler, MarshalTypeRef = typeof(UTF8Marshaler))]") string "string"
and on line 61, replace this line:
%typemap(imtype) const string & "string"
with this line:
%typemap(imtype, inattributes="[MarshalAs(UnmanagedType.CustomMarshaler, MarshalTypeRef = typeof(UTF8Marshaler))]", outattributes="[return: MarshalAs(UnmanagedType.CustomMarshaler, MarshalTypeRef = typeof(UTF8Marshaler))]") string & "string"
Lo and behold, everything works. Read the linked article for a good understanding of how this works.
I am a newbie to C++. I want to get the content of the clipboard, which might contain Unicode chars, append a div tag with some content formatted in HTML and set that back to clipboard.
I have achieved successfully in getting the content and appending it. But could not set it back to the clipboard as an HTML text. I have achieved setting as simple text. Here is my code:
#include <shlwapi.h>
#include <iostream>
#include <conio.h>
#include <stdio.h>
using namespace std;
wstring getClipboard(){
if (OpenClipboard(NULL)){
HANDLE clip = GetClipboardData(CF_UNICODETEXT);
WCHAR * c;
c = (WCHAR *)clip;
CloseClipboard();
return (WCHAR *)clip;
}
return L"";
}
bool setClipboard(wstring textToclipboard)
{
if (OpenClipboard(NULL)){
EmptyClipboard();
HGLOBAL hClipboardData;
size_t size = (textToclipboard.length()+1) * sizeof(WCHAR);
hClipboardData = GlobalAlloc(NULL, size);
WCHAR* pchData = (WCHAR*)GlobalLock(hClipboardData);
memcpy(pchData, textToclipboard.c_str(), size);
SetClipboardData(CF_UNICODETEXT, hClipboardData);
GlobalUnlock(hClipboardData);
CloseClipboard();
return true;
}
return false;
}
int main (int argc, char * argv[])
{
wstring s = getClipboard();
s += std::wstring(L"some extra text <b>hello</b>");
setClipboard(s);
getch();
return 0;
}
I did try using the code described here and read the doc here. But I couldn't make it work. What I tried could be way off track or completely wrong.
Update: The code below is what I tried after the modifications suggested by Cody Gray to the original code presented here:
bool CopyHTML2(WCHAR *html ){
wchar_t *buf = new wchar_t [400 + wcslen(html)];
if(!buf) return false;
static int cfid = 0;
if(!cfid) cfid = RegisterClipboardFormat("HTML Format");
// Create a template string for the HTML header...
wcscpy(buf,
L"Version:0.9\r\n"
L"StartHTML:00000000\r\n"
L"EndHTML:00000000\r\n"
L"StartFragment:00000000\r\n"
L"EndFragment:00000000\r\n"
L"<html><body>\r\n"
L"<!--StartFragment -->\r\n");
// Append the HTML...
wcscat(buf, html);
wcscat(buf, L"\r\n");
// Finish up the HTML format...
wcscat(buf,
L"<!--EndFragment-->\r\n"
L"</body>\r\n"
L"</html>");
wchar_t *ptr = wcsstr(buf, L"StartHTML");
wsprintfW(ptr+10, L"%08u", wcsstr(buf, L"<html>") - buf);
*(ptr+10+8) = L'\r';
ptr = wcsstr(buf, L"EndHTML");
wsprintfW(ptr+8, L"%08u", wcslen(buf));
*(ptr+8+8) = '\r';
ptr = wcsstr(buf, L"StartFragment");
wsprintfW(ptr+14, L"%08u", wcsstr(buf, L"<!--StartFrag") - buf);
*(ptr+14+8) = '\r';
ptr = wcsstr(buf, L"EndFragment");
wsprintfW(ptr+12, L"%08u", wcsstr(buf, L"<!--EndFrag") - buf);
*(ptr+12+8) = '\r';
// Open the clipboard...
if(OpenClipboard(0)) {
EmptyClipboard();
HGLOBAL hText = GlobalAlloc(GMEM_MOVEABLE |GMEM_DDESHARE, wcslen(buf)+4);
wchar_t *ptr = (wchar_t *)GlobalLock(hText);
wcscpy(ptr, buf);
GlobalUnlock(hText);
SetClipboardData(cfid, hText);
CloseClipboard();
GlobalFree(hText);
}
// Clean up...
delete [] buf;
return true;
}
This code compiles successfully, But I get the following error at SetClipboardData : HEAP[Project1.exe]: Heap block at 007A8530 modified at 007A860A past requested size of d2
Project1.exe has triggered a breakpoint.
Please guide me on how to proceed. I am using Visual Studio Express 2012 on Windows 8. Thanks.
You're mismatching ANSI (narrow) and Unicode (wide) strings.
Unlike the wcscpy function, the w in the wsprintf function doesn't stand for "wide", it stands for "Windows". It is part of the Win32 API, rather than the C runtime library. All of the Win32 API functions that work with strings have two versions, one suffixed with an A that deals with ANSI strings and another suffixed with a W that deals with wide strings. The headers hide all of this from you with macros. I explain all of this in more detail here—recommended reading.
Anyway, the simple fix here is to explicitly call the wide variant of that function, since you're correctly using wide strings everywhere else. Make all the calls to wsprintf look like this:
wchar_t *ptr = wcsstr(buf, L"StartHTML");
wsprintfW(ptr+10, L"%08u", wcsstr(buf, L"<html>") - buf);
*(ptr+10+8) = L'\r';
Alternatively, you could use the swprintf function provided by the C runtime library instead of the Win32 version. This one works just like the wcsstr and wcscpy functions you're using elsewhere. The w in the name means "wide". The documentation for this series of functions is here.
Note also that when you use character or string literals, they also need to be wide characters. You accomplish that by prepending them with an L. You do that some places, but miss doing it others. Make sure that you do it consistently.
The compiler should warn you about all this, though. You just need to make sure you turn your warning level up and don't ignore any of the warnings. Also make sure that both the UNICODE and _UNICODE preprocessor symbols are defined globally for your project. That will ensure that you are always calling the Unicode/wide versions of functions. Although that should be the default for all new projects.
This is the function I came up with the help of Jochen Arndt at codeproject.com. Hope this helps somebody. Here is a complete working code, if you are interested in checking this out.
It still has one problem. That is when pasted to onenote alone, it pastes gibberish after a anchor tag. It does not happen with Word, PowerPoint or Excel. And it does not have this problem for normal English language texts. If you have a solution for this, please do let me know. The problem seems to be with OneNote. Not with the code.
bool setClipboard(LPCWSTR lpszWide){
int nUtf8Size = ::WideCharToMultiByte(CP_UTF8, 0, lpszWide, -1, NULL, 0, NULL, NULL);
if (nUtf8Size < 1) return false;
const int nDescLen = 105;
HGLOBAL hGlobal = ::GlobalAlloc(GMEM_MOVEABLE, nDescLen + nUtf8Size);
if (NULL != hGlobal)
{
bool bErr = false;
LPSTR lpszBuf = static_cast<LPSTR>(::GlobalLock(hGlobal));
LPSTR lpszUtf8 = lpszBuf + nDescLen;
if (::WideCharToMultiByte(CP_UTF8, 0, lpszWide, -1, lpszUtf8, nUtf8Size, NULL, NULL) <= 0)
{
bErr = true;
}
else
{
LPCSTR lpszStartFrag = strstr(lpszUtf8, "<!--StartFragment-->");
LPCSTR lpszEndFrag = strstr(lpszUtf8, "<!--EndFragment-->");
lpszStartFrag += strlen("<!--StartFragment-->") + 2;
int i = _snprintf(
lpszBuf, nDescLen,
"Version:1.0\r\nStartHTML:%010d\r\nEndHTML:%010d\r\nStartFragment:%010d\r\nEndFragment:%010d\r\n",
nDescLen,
nDescLen + nUtf8Size - 1, // offset to next char behind string
nDescLen + static_cast<int>(lpszStartFrag - lpszUtf8),
nDescLen + static_cast<int>(lpszEndFrag - lpszUtf8));
}
::GlobalUnlock(hGlobal);
if (bErr)
{
::GlobalFree(hGlobal);
hGlobal = NULL;
}
// Get clipboard id for HTML format...
static int cfid = 0;
cfid = RegisterClipboardFormat("HTML Format");
// Open the clipboard...
if(OpenClipboard(0)) {
EmptyClipboard();
HGLOBAL hText = GlobalAlloc(GMEM_MOVEABLE |GMEM_DDESHARE, strlen(lpszBuf)+4);
char *ptr = (char *)GlobalLock(hText);
strcpy(ptr, lpszBuf);
GlobalUnlock(hText);
::SetClipboardData(cfid, hText);
CloseClipboard();
GlobalFree(hText);
}
}
return NULL != hGlobal;
}
Your problem comes from the use of wchar_t instead of char in the cited example which makes you wrong on the offset computations.
I would however recommend you avoiding the use of wchar_t for transfering UNICODE text to the clipboard. Indeed, UTF-8 char could coded with a sequence of bytes comprised between 1 and 4 bytes, while wchar_t on Windows is a fixed 2 bytes type.
As explained in the Microsoft doc refered in your email, the content of the clipboard shall be UNICODE, which happens to be the same as ASCII for the characters contained in the header of the clipboard memory.
To transfert UNICODE in the clipboard, you can do it using the standard char C++ functions to prepare the content sent to clipboard (std::string for eg.)
While the cited example works, please find here another code sample using C++ framework that can actually copy UTF-8 chars to the clipboard in HTML format:
void copyHTMLtoClipboard(const std::string& html) {
std::string contextStart("Version:0.9\r\nStartHTML:0000000000\r\nEndHTML:0000000000\r\nStartFragment:0000000000\r\nEndFragment:0000000000\r\n<html><body>\r\n<!--StartFragment -->\r\n");
std::string contextEnd("\r\n<!--EndFragment -->\r\n</body></html>");
std::stringstream aux;
aux << contextStart << html << contextEnd;
std::string res = aux.str();
size_t htmlStart = 105 * sizeof(char);
size_t fragmentStart = 119 * sizeof(char);
size_t htmlEnd = res.size() * sizeof(char);
size_t fragmentEnd = htmlEnd - 35 * sizeof(char);
aux.fill('0');
aux.width(10);
aux.seekp(23);
aux << htmlStart;
aux.seekp(43);
aux.fill('0');
aux.width(10);
aux << htmlEnd;
aux.seekp(69);
aux.fill('0');
aux.width(10);
aux << fragmentStart;
aux.seekp(93);
aux.fill('0');
aux.width(10);
aux << fragmentEnd;
res = aux.str();
HGLOBAL hdst = GlobalAlloc(GMEM_MOVEABLE | GMEM_DDESHARE, htmlEnd + sizeof(char));
LPSTR dst = (LPSTR)GlobalLock(hdst);
memcpy(dst, res.c_str(), htmlEnd);
dst[htmlEnd] = 0;
GlobalUnlock(hdst);
OpenClipboard(NULL);
EmptyClipboard();
SetClipboardData(RegisterClipboardFormat(L"HTML Format"), hdst);
CloseClipboard();
GlobalFree(hdst);
}
Note that this code was compiled defining the macros _UNICODE and UNICODE.