【原创】 VC++各种字符串类型转换

包括VC编程时常用的Unicode和Char互转，CString和std::string互转， 其他的转换可以由这个几个转化间接得到

// convert.h

 
#include <string>

#ifndef  _CONVERT_H_
#define  _CONVERT_H_

 
class CConvert
{
public:
    CConvert(void);
    virtual ~CConvert(void);

    static int Ansi2Unicode(__in const char* pSrc,  wchar_t *pDst, __in size_t nChsOfDst); 

    static int Unicode2Ansi(__in const wchar_t * pSrc, char* pDst, __in size_t nBytesOfDst);  

    static std::string CString2String(CString str);


    static CString String2CString(const std::string& str);
};

#endif

 //convert.cpp

#include "StdAfx.h"
#include "Convert.h"


CConvert::CConvert(void)
{
}


CConvert::~CConvert(void)
{
}

int CConvert::Ansi2Unicode(__in const char* pSrc,  wchar_t *pDst, __in size_t nChsOfDst)
{ 
    if (NULL == pDst)
    {
        int nChsOfDstNeed = MultiByteToWideChar(CP_ACP, 0, pSrc, -1, NULL, 0); //unicdoe缓冲区需要的字符数，包括\0; 
        return nChsOfDstNeed;
    }


    return MultiByteToWideChar(CP_ACP, 0, pSrc, -1, pDst, nChsOfDst);  
}


int CConvert::Unicode2Ansi(__in const wchar_t * pSrc, char* pDst, __in size_t nBytesOfDst)
{
    if (NULL == pDst)
    {
        int nBytesOfDstNeed = WideCharToMultiByte(CP_ACP, 0, pSrc, -1, NULL, 0, NULL, NULL); //返回需要写的字节数，包括末尾的\0;
        return nBytesOfDstNeed;
    }

    return WideCharToMultiByte(CP_ACP, 0, pSrc, -1, pDst, nBytesOfDst, NULL, NULL); //返回需要写的字节数，包括末尾的\0; 
}


std::string CConvert::CString2String(CString str)
{
    int len = str.GetLength();
    TCHAR* pSrc = str.GetBuffer(len); 

    if (NULL == pSrc)
    {
        return NULL;
    }

    int nBytesOfDst = Unicode2Ansi(pSrc, NULL, 0);
    if (0 == nBytesOfDst)
    {
        return NULL;
    }

    char *pDst = new char[nBytesOfDst / sizeof(char)];
    memset(pDst, 0, nBytesOfDst);

    Unicode2Ansi(pSrc, pDst, nBytesOfDst);

    std::string strRet(pDst);
    delete[] pDst;

    return strRet; 
}


CString CConvert::String2CString(const std::string& str)
{
    CString strRet(str.c_str());

    return strRet;
}

//使用代码实例

void CMFCMacrosDlg::Ansi2Unicode()
{ 
    CConvert obj;
    
    char* pSrc = "cuihao";
    int nChsOfDst = obj.Ansi2Unicode(pSrc, NULL, 0); 
    wchar_t *pDst = new wchar_t[nChsOfDst]; 
    nChsOfDst = obj.Ansi2Unicode(pSrc, pDst, nChsOfDst);

    MessageBox(CString(pDst));
    
    delete[] pDst;
}


void CMFCMacrosDlg::Unicode2Ansi()
{
    // TODO: 在此添加控件通知处理程序代码;
    CConvert obj;

    wchar_t *pSrc = L"cuihao";

    int nBytesOfDst = obj.Unicode2Ansi(pSrc, NULL, 0);

    char *pDst = new char[nBytesOfDst / sizeof(char)];  //包含\0

    obj.Unicode2Ansi(pSrc, pDst, nBytesOfDst);

    MessageBox(CString(pDst));

    delete[] pDst;
}


void CMFCMacrosDlg::CString2String()
{
    // TODO: 在此添加控件通知处理程序代码;

    CString str("cuihao");

    CConvert obj;
     
    std::string strInfo = obj.CString2String(str);
    
    MessageBox(obj.String2CString(strInfo));
}


void CMFCMacrosDlg::String2CString()
{ 
    std::string str("cuihao");

    CConvert obj;
    CString strRet = obj.String2CString(str); 
}