C#DataTable.Load和DbDataAdapter.Fill方法的比较。附取消限制的方法

                SqlCommand com = new SqlCommand("select * from LoginUser", con);
                SqlDataReader dr = com.ExecuteReader();
                DataSet ds = new DataSet();
                DataTable dt = new DataTable();
                ds.Tables.Add(dt);
                ds.Load(dr, LoadOption.OverwriteChanges, dt);
                ds.EnforceConstraints = false;
                return dt;