关于绑定gridview的升序降序有关问题，为嘛只能升序没法降序呢？有代码

关于绑定gridview的升序降序问题，为嘛只能升序没法降序呢？有代码

    public void DataBind(string sortField)

    {

        string pro_manager = Session["realname"].ToString();

        string strSql = "select a.*,b.company from unconfirmed_quotes a,customer_info b ";

        strSql += " where a.pro_manager='" + pro_manager + "' and a.customer=b.realname";

        using (MySqlConnection conn = new MySqlConnection("database=test;data source=127.0.0.1;user id=root;password=root;port=3306") )

        {

            conn.Open();

            MySqlDataAdapter adt = new MySqlDataAdapter(strSql, conn);

            DataSet ds = new DataSet();

            adt.Fill(ds);

            DataView dvw = ds.Tables[0].DefaultView;

            if (!string.IsNullOrEmpty(sortField))

                dvw.Sort = sortField;

            this.GridView_UnconfirmedQuotes.DataSource = dvw.Table;

            this.GridView_UnconfirmedQuotes.DataBind();

        }

    }


    //public void bind()

    //{


    //    string pro_manager = Session["realname"].ToString();

    //    string strSql = "select a.*,b.company from unconfirmed_quotes a,customer_info b ";

    //    strSql += " where a.pro_manager='" + pro_manager + "' and a.customer=b.realname";


    //    MySqlConnection conn = new MySqlConnection("database=test;data source=127.0.0.1;user id=root;password=root;port=3306");

    //    conn.Open();

    //    MySqlDataAdapter adt = new MySqlDataAdapter(strSql, conn);

    //    DataSet ds = new DataSet();

        

    //    adt.Fill(ds);

    //    DataView view = ds.Tables[0].DefaultView;

    //    string sort = (string)ViewState["SortOrder"] + " " + (string)ViewState["OrderDire"];

    //    view.Sort = sort;

    //    GridView_UnconfirmedQuotes.DataSource = view;

    //    GridView_UnconfirmedQuotes.DataBind();

    //    conn.Close();

    //}



    protected void Unconfirm_Sorting(object sender, GridViewSortEventArgs e)

    {

        if (ViewState["SortField"].ToString() == e.SortExpression)

        {

            ViewState["SortField"] += " DESC";

        }

        else

            ViewState["SortField"] = e.SortExpression;


        DataBind(ViewState["SortField"].ToString());

        //string sPage = e.SortExpression;

        //if (ViewState["SortOrder"].ToString() == sPage)

        //{

        //    if (ViewState["OrderDire"].ToString() == "Desc")

        //        ViewState["OrderDire"] = "ASC";

        //    else

        //        ViewState["OrderDire"] = "Desc";

        //}

        //else

        //{

        //    ViewState["SortOrder"] = e.SortExpression;

        //}

        //bind();