The following will sort the records in the datatable based on the data column age.
DataTable dt = new DataTable();
DataRow dr;
dr = dt.NewRow();
dr[0] = 21;
dr[1] = "AAA";
dt.Rows.Add(dr);
dr = dt.NewRow();
dr[0] = 20;
dr[1] = "AAA";
dt.Rows.Add(dr);
dr = dt.NewRow();
dr[0] = 22;
dr[1] = "AAA";
dt.Rows.Add(dr);
//sorting
dt.AsEnumerable().Select(dr=>dr["age"]).OrderbyDesc(o=>o).ToList();