这是我摘录出来的VC6.0下
CString mstr;
mstr+='7';
double m_num1=wcstod(mstr,NULL);
错误为：cannot convert parameter 1 from 'class CString' to 'const unsigned short *'
        No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called

cannot convert parameter 1 from 'class CString' to 'const unsigned short *'

原因 写的很明确了哦

    CString mstr;
    mstr += _T('7');
    double m_num = _tcstod( mstr, NULL );