Unable to convert the CStringW to CStringA

c++ string mfc cstring mbcs
A B picture A B · Feb 26, 2014 · Viewed 7k times · Source

I am working on one project where I have stucked on one problem of converting CStringW to CStringA for multibyte string like Japanese Language.

I am loading the string from string resources using LoadString() Method. I have tried following code but it does not seem to work.

CStringW csTest;
csTest.LoadString(JAPANESE_STRING);
CStringA Msg = CStringA(csTest); // Msg has been returned blank string

And 

std::string Msg = CW2A(csTest);// Msg has been returned blank string

I have also tried wcstombs() too.

Can anyone tell me how I can convert CStringW to CString? Thanks in advance.

Answer

Mr.C64 picture Mr.C64 · Feb 26, 2014

CStringW stores Unicode UTF-16 strings.

What encoding do you expect for your CStringA?

Do you want UTF-8?
In this case, you can do:

// strUtf16 is a CStringW.
// Convert from UTF-16 to UTF-8
CStringA strUtf8 = CW2A(strUtf16, CP_UTF8);

Talking about CStringA without specifying an encoding doesn't make sense.

The second parameter of CW2A is a what is passed to WideCharToMultiByte() Win32 API as CodePage (note that CW2A is essentially a convenient safe C++ RAII wrapper around this API). If you follow this API documentation, you can find several "code page" values (i.e. encodings).

Related questions

MFC: std::string vs CString?

Using C++ with MFC. Coming from a C# background I typically just use string for all, well, strings. I use them for class members, method parameters, and method return values. Now in C++ I've got std::string, CString, char *, LPCTSTR, …

Read More
How to convert std:string to CString in unicode project

I have a std::string. I need to convert this std:string to a Cstring. I try to use the .c_str() but it's only for non-unicode project and i use unicode project ( because non unicode project are depreceated wiht …

Read More
What is `CString`?

Why do I see some code using CStrings declared differently. Some use this format char a_c_string []; While others use CString another_c_string; Is there a difference? All the references I have found on CStrings declare it as …

Read More