字符串转float型

 TCHAR* pTchar = NULL;
            double dMin = ::_tcstod( csMin, &pTchar );
            double dMax = ::_tcstod( csMax, &pTchar );
            if ( dMax < dMin )
            {
                m_editMetaPPMMin[ nIndex ].SetWindowText( csMax );
                m_editMetaPPMMax[ nIndex ].SetWindowText( csMin );
            }