How to add sorting to gridview based on any columns?

   protected void SortRecords(object sender, GridViewSortEventArgs e)

    {

        DataTable dataTable = GridDataSource();



        if (dataTable != null)

        {

            DataView dataView = new DataView(dataTable);

            dataView.Sort = GetSortExpression(e);

            grdBlock.DataSource = dataView;

            grdBlock.DataBind();

        }

    }



    private string GetSortExpression(GridViewSortEventArgs e)

    {

        string sortDirection = string.Empty;

        // if clicked on the same column twice then let it toggle the sort order, else reset to ascending

        if (ViewState["SortExpression"] != null)

        {

            if (!ViewState["SortExpression"].ToString().Equals(e.SortExpression.ToLower()))

            {

                ViewState["SortDirection"] = null;

            }

        }



        if (ViewState["SortDirection"] != null)

        {

            if (ViewState["SortDirection"].ToString().Equals("ASC"))

            {

                sortDirection = "DESC";

                ViewState["SortDirection"] = "DESC";

            }

            else

            {

                sortDirection = "ASC";

                ViewState["SortDirection"] = "ASC";

            }

        }

        else

        {

            ViewState["SortDirection"] = "ASC";

        }

        ViewState["SortExpression"] = e.SortExpression.ToLower();



        return e.SortExpression + " " + sortDirection;

    }



    protected DataTable GridDataSource()

    {

        DataTable dTable = new DataTable();

        DataAccessClass dao = new DataAccessClass();

        DataSet ds = new DataSet();

        try

        {

            SqlParameter Blockname = new SqlParameter("@Blockname", null);

            SqlParameter[] DBblock = new SqlParameter[1] { Blockname };

            ds = dao.ExecuteSelect("spGetBlockData", DBblock);

            dTable = ds.Tables[0];

            

        }

        catch (Exception ex)

        {



        }

        finally

        { 

            ds.Dispose();

          

        }

        return dTable;

    }

Thanks,
Sanjay