验证IP地址的有效性

DWORD        dwIP;

HWND hwndIPAddr=GetDlgItem(IDC_IPADDR_SEND)->m_hWnd;((CIPAddressCtrl*)GetDlgItem(IDC_IPADDR_SEND))->GetAddress(dwIP);if(4 != ::SendMessage( hwndIPAddr, IPM_GETADDRESS, 0, ( LPARAM )&dwIP)){::MessageBox( m_hWnd, _T("输入的 IP 地址不完整。  "), _T("错误"), MB_OK | MB_ICONWARNING | MB_TOPMOST );        ::SetFocus( hwndIPAddr );        return;}