VC2005中list control控件如何获得选中的行

void SegmentSeting::OnNMDblclkListData(NMHDR *pNMHDR, LRESULT *pResult)
{
// TODO: 在此添加控件通知处理程序代码

*pResult = 0;

UpdateData(TRUE);

POSITION pos= m_datadisplay.GetFirstSelectedItemPosition();

if( pos != NULL )
{
displaylist_currentpos= m_datadisplay.GetNextSelectedItem( pos )+1;

segmentdata val;
if( getsegmentnode( displaylist_currentpos,val) )
{
CurrentSegmentID= displaylist_currentpos;
m_segmentid.Format( "%d",CurrentSegmentID);
m_data1.Format("%f",val.start);
m_data2.Format("%f",val.finish);
m_data3.Format("%f",val.slope);
m_data4.Format("%f",val.keeptime);
}
}

UpdateData(FALSE);

}