string与wstring转换

• 方法一：MultiByteToWideChar、WideCharToMultiByte

 1 BOOL StringToWString(const std::string &str,std::wstring &wstr)
 2  {    
 3      int nLen = (int)str.length();    
 4      wstr.resize(nLen,L' ');
 5  
 6      int nResult = MultiByteToWideChar(CP_ACP,0,(LPCSTR)str.c_str(),nLen,(LPWSTR)wstr.c_str(),nLen);
 7  
 8      if (nResult == 0)
 9      {
10          return FALSE;
11      }
12  
13      return TRUE;
14  }
15  //wstring高字节不为0，返回FALSE
16  BOOL WStringToString(const std::wstring &wstr,std::string &str)
17  {    
18      int nLen = (int)wstr.length();    
19      str.resize(nLen,' ');
20  
21      int nResult = WideCharToMultiByte(CP_ACP,0,(LPCWSTR)wstr.c_str(),nLen,(LPSTR)str.c_str(),nLen,NULL,NULL);
22  
23      if (nResult == 0)
24      {
25          return FALSE;
26      }
27  
28      return TRUE;
29  }

• 方法二：std::copy

 1 std::wstring StringToWString(const std::string &str)
 2  {
 3      std::wstring wstr(str.length(),L' ');
 4      std::copy(str.begin(), str.end(), wstr.begin());
 5      return wstr; 
 6  }
 7  
 8  //只拷贝低字节至string中
 9  std::string WStringToString(const std::wstring &wstr)
10  {
11      std::string str(wstr.length(), ' ');
12      std::copy(wstr.begin(), wstr.end(), str.begin());
13      return str; 
14  }