CString&CStringA&CStringW之间的相互转换

　　在做MFC编程的时候，时常会碰到CString、CStringA、CStringW之间相互转换的问题，也即chat字符串与wchar_t字符串相互转换的问题。

现本人写了一个它们之间相互转换的函数，代码如下：

头文件CStringToolEx.h

#ifndef _CSTRING_TOOL_EX_
#define _CSTRING_TOOL_EX_

#include <cstringt.h>

//
// CString转CStringA
//
#ifndef CStrT2CStrA
#ifdef _UNICODE
#define CStrT2CStrA(cstr) CStrW2CStrA((cstr))
#else
#define CStrT2CStrA(cstr) (cstr)
#endif
#endif

//
// CString转CStringW
//
#ifndef CStrT2CStrW
#ifdef _UNICODE
#define CStrT2CStrW(cstr) (cstr)
#else
#define CStrT2CStrW(cstr) CStrA2CStrW((cstr))
#endif
#endif

//
// CStringA转CString
//
#ifndef CStrA2CStrT
#ifdef _UNICODE
#define CStrA2CStrT(cstr) CStrA2CStrW((cstr))
#else
#define CStrA2CStrT(cstr) (cstr)
#endif
#endif

//
// CStringW转CString
//
#ifndef CStrW2CStrT
#ifdef _UNICODE
#define CStrW2CStrT(cstr) (cstr)
#else
#define CStrW2CStrT(cstr) CStrW2CStrA((cstr))
#endif
#endif

//
// CStringA转CStringW
//
CStringW CStrA2CStrW(const CStringA &cstrSrcA);

//
// CStringW转CStringA
//
CStringA CStrW2CStrA(const CStringW &cstrSrcW);

#endif

源文件CStringToolEx.cpp

#include "stdafx.h"
#include "CStringToolEx.h"
#include <cstringt.h>

//
// CStringA转CStringW
//
CStringW CStrA2CStrW(const CStringA &cstrSrcA)
{
    int len = MultiByteToWideChar(CP_ACP, 0, LPCSTR(cstrSrcA), -1, NULL, 0);
    wchar_t *wstr = new wchar_t[len];
    memset(wstr, 0, len*sizeof(wchar_t));
    MultiByteToWideChar(CP_ACP, 0, LPCSTR(cstrSrcA), -1, wstr, len);
    CStringW cstrDestW = wstr;
    delete[] wstr;

    return cstrDestW;
}

//
// CStringW转CStringA
//
CStringA CStrW2CStrA(const CStringW &cstrSrcW)
{
    int len = WideCharToMultiByte(CP_ACP, 0, LPCWSTR(cstrSrcW), -1, NULL, 0, NULL, NULL);
    char *str = new char[len];
    memset(str, 0, len);
    WideCharToMultiByte(CP_ACP, 0, LPCWSTR(cstrSrcW), -1, str, len, NULL, NULL);
    CStringA cstrDestA = str;
    delete[] str;

    return cstrDestA;
}

使用示例:

    CString  cstrName = TEXT("Hello Kitty");
    CStringA cstraName = CStrT2CStrA(cstrName);   //CString to CStringA
    CStringW cstrwName = CStrT2CStrW(cstrName);   //CString to CStringW
    ::MessageBoxA(NULL, cstraName, "CStringToolEx Test", MB_OK);
    ::MessageBoxW(NULL, cstrwName, L"CStringToolEx Test", MB_OK);

    CStringA cstraAddr = "Anhui Anqing";
    CString  cstrAddr  = CStrA2CStrT(cstraAddr);    //CStringA to CString
    CStringW cstrwAddr = CStrA2CStrW(cstraAddr);    //CStringA to CStringW
    ::MessageBox(NULL, cstrAddr, TEXT("CStringToolEx Test"), MB_OK);
    ::MessageBoxW(NULL, cstrwAddr, L"CStringToolEx Test", MB_OK);

    CStringW cstrwGender = L"Male";
    CString  cstrGender  = CStrW2CStrT(cstrwGender);   //CStringW to CString
    CStringA cstraGender = CStrW2CStrA(cstrwGender);   //CStringW to CStringA
    ::MessageBox(NULL, cstrGender, TEXT("CStringToolEx Test"), MB_OK);
    ::MessageBoxA(NULL, cstraGender, "CStringToolEx Test", MB_OK);