Summary
Encountered problem in convert from string to CString (LPCWSTR), and the reverse convert, find out the way to convert between these two types and tested in Visual Studio with successful result.
The unicode setting is configured in the Visual Studio project property page –> Configuration Properties –> General –> Character Set –> Use Unicode Character Set, as below picture shows,
Different string types description as below, as How to convert std::string to LPCSTR? mentioned,
LPSTR
– (long) pointer to string – char *
LPCSTR
– (long) pointer to constant string – const char *
LPWSTR
– (long) pointer to Unicode (wide) string – wchar_t *
LPCWSTR
– (long) pointer to constant Unicode (wide) string – const wchar_t *
LPTSTR
– (long) pointer to TCHAR (Unicode if UNICODE is defined, ANSI if not) string – TCHAR *
LPCTSTR
– (long) pointer to constant TCHAR string – const TCHAR *
C++ convert from string to LPCWSTR
As you know, std::string
is char*
type, while LPCWSTR
,LPWSTR
or CString
is wchar_t*
as long as the Visual Studio configured as Unicode Character Set.
I am using How to convert std::string to LPCSTR? solution as below code solved this problem,
LPWSTR ConvertString(const std::string& instr)
{
// Assumes std::string is encoded in the current Windows ANSI codepage
int bufferlen = ::MultiByteToWideChar(CP_ACP, 0, instr.c_str(), instr.size(), NULL, 0);
if (bufferlen == 0)
{
// Something went wrong. Perhaps, check GetLastError() and log.
return 0;
}
// Allocate new LPWSTR - must deallocate it later
LPWSTR widestr = new WCHAR[bufferlen + 1];
::MultiByteToWideChar(CP_ACP, 0, instr.c_str(), instr.size(), widestr, bufferlen);
// Ensure wide string is null terminated
widestr[bufferlen] = 0;
// Do something with widestr
return widestr;
//delete[] widestr;
}
Refer to the How to convert string to LPCTSTR? solution 5, it is the similar solution as above by using MultiByteToWideChar
function,
std::wstring s2ws(const std::string& s)
{
int len;
int slength = (int)s.length() + 1;
len = MultiByteToWideChar(CP_ACP, 0, s.c_str(), slength, 0, 0);
wchar_t* buf = new wchar_t[len];
MultiByteToWideChar(CP_ACP, 0, s.c_str(), slength, buf, len);
std::wstring r(buf);
delete[] buf;
return r;
}
std::string s;
#ifdef UNICODE
std::wstring stemp = s2ws(s); // Temporary buffer is required
LPCWSTR result = stemp.c_str();
#else
LPCWSTR result = s.c_str();
#endif>
C++ convert from LPCWSTR to string
To convert from LPCWSTR
to string
, can split into two steps, first step convert fromCString
to wchar_t
, 2nd step, convert from wchar_t
to char*
, as below code shows,
//convert from CString to char* , first from CString to wchar_t then to char *
wchar_t wCharString = sFile.GetBuffer(sFile.GetLength()+1); //CString to wchar_t
size_t origsize = wcslen(wCharString) + 1;
size_t convertedChars = 0;
char gszFile[100] = {0};
wcstombs_s(&convertedChars, gszFile, origsize, wCharString , _TRUNCATE); //from wchar_t to char*
Below code from MSDN is working perfectly for the conversion from wchar_t*
to char*
by using wcstombs_s
function,
// crt_wcstombs_s.c
// This example converts a wide character
// string to a multibyte character string.
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#define BUFFER_SIZE 100
int main( void )
{
size_t i;
char *pMBBuffer = (char *)malloc( BUFFER_SIZE );
wchar_t*pWCBuffer = L"Hello, world.";
printf( "Convert wide-character string:n" );
// Conversion
wcstombs_s(&i, pMBBuffer, (size_t)BUFFER_SIZE,
pWCBuffer, (size_t)BUFFER_SIZE );
// Output
printf(" Characters converted: %un", i);
printf(" Multibyte character: %snn",
pMBBuffer );
// Free multibyte character buffer
if (pMBBuffer)
{
free(pMBBuffer);
}
}