private void loc_arr(string mm_id)
{
int id = Convert.ToInt32(mm_id);
DataTable dtLoc = ds.Tables["mn"];
var loc = from lc in dtLoc.AsEnumerable()
                      where lc["MM_ID"] == id
                      select new
                      {
                        mm_id = lc["mm_id"],
                        sec_mod = lc["SEC_MOD"],
                        sec_num = lc["SEC_NUM"],
                        sec = lc["SEC"],
                        lhr = lc["LHR"]
                      };
            foreach (var lc in loc)
            {
                Console.WriteLine("mm_id: {0}", lc.mm_id.ToString());  
                Console.WriteLine("sec_mod: {0}", lc.sec_mod.ToString());  
                Console.WriteLine("sec_num: {0}", lc.sec_num.ToString()); 
                Console.WriteLine("sec: {0}", lc.sec.ToString());    
                Console.WriteLine("lhr: {0}", Math.Abs(Convert.ToInt32(lc.lhr)).ToString());  
                Console.WriteLine("");
            } 
}     

where lc["MM_ID"] == id

where (int)lc["MM_ID"] == id