C++ WString與String互相轉換

std::wstring StringToWString(const std::string& str) 
{
    int num = MultiByteToWideChar(CP_UTF8, 0, str.c_str(), -1, NULL, 0);
    wchar_t *wide = new wchar_t[num];
    MultiByteToWideChar(CP_UTF8, 0, str.c_str(), -1, wide, num);
    std::wstring w_str(wide);
    delete[] wide;
    return w_str;
}

std::string WStringToString(const std::wstring &wstr)
{
    std::string str;
    int nLen = (int)wstr.length();
    str.resize(nLen, ' ');
    int nResult = WideCharToMultiByte(CP_ACP, 0, (LPCWSTR)wstr.c_str(), nLen, (LPSTR)str.c_str(), nLen, NULL, NULL);
    if (nResult == 0)
    {
        return "";
    }
    return str;
}

 如果程序有時候用utf-8中文的話，一般從網絡傳回的數據是utf-8，StringToWString后是亂碼，那么需要使用下面方案

std::wstring StringToWString(const std::string& str)
{
    setlocale(LC_ALL, "chs");
    const char* point_to_source = str.c_str();
    size_t new_size = str.size() + 1;
    wchar_t *point_to_destination = new wchar_t[new_size];
    wmemset(point_to_destination, 0, new_size);
    mbstowcs(point_to_destination, point_to_source, new_size);
    std::wstring result = point_to_destination;
    delete[]point_to_destination;
    setlocale(LC_ALL, "C");
    return result;
}