How to call a part of a function not the whole function in somewhere?

I am trying to call a condition which is defined inside of a function in somewhere else but I don't know if it is possible. this function is a member of a class:

  void CMainDlg::OnTcnSelchangeTab1(NMHDR *pNMHDR, LRESULT *pResult)
{
    int ii=M_TabCtrl1.GetCurSel();  

if(ii==0)
        {
         GetDlgItem....
         GetDlgItem....
        }
else if(ii==1)
   {
    ///GetDlgItem....
   ///GetDlgItem....
   }
else
  {
  ////
  }
  }
    // TODO: Add your control notification handler code here
    *pResult = 0;
}

I am trying to call and execute the following loop directly somewhere else but I don't know how.

if(ii==0)
    {
GetDlgItem....
GetDlgItem....
}