Adding sorted list to DataTable Row

Question

I am trying to add IEnumerable items of string to a datatable row, but can't get it sorted. I want to get an output of 

 

james,john

Mary,Ann

Edward,Anthony

 

but I am getting  james,johnMary,AnnEdward,Anthony

Below is my code. Any help will be appreciated.

 

private void addToDataTable<T>(IEnumerable<T> rDataRow, string dataRowType)
       {
           try
           {
               foreach (var r in rDataRow)
               {
            var type = r.GetType();
                DataRow dr = reportData.NewRow();

              var ListItems = "";


                       if (type.GetProperty("admin") != null)
                       {
                           foreach (var t in (IEnumerable)type.GetProperty("admin").GetValue(r, null))
                           {

                               ListItems += t;
                           }
                           dr.SetField(dcAdmin, ListItems);
                       }
                       reportData.Rows.Add(dr);
            }
        }
    }