GridView 排序

<asp:BoundField DataField="filesize" HeaderText="大小"  SortExpression="id"/>

/// <summary>
    /// 存储选定列当前排序状态
    /// </summary>
    public SortDirection GridViewSortDirection
    {
        get
        {
            if (ViewState["sortDirection"] == null)
                ViewState["sortDirection"] = SortDirection.Ascending;
            return (SortDirection)ViewState["sortDirection"];
        }
        set { ViewState["sortDirection"] = value; }
    }
    protected void softlistshow_Sorting(object sender, GridViewSortEventArgs e)
    {
        try
        {
//如果是嵌套的话 可以这么找到控件
//   GridView re = (GridView)sender;
            string sortExpression = e.SortExpression;
            DataSet ds1 = new DataSet();
            ds1 = sf.software_pro_Jgetvisionlist(id);
            DataTable dt = ds1.Tables[0];
            if (GridViewSortDirection == SortDirection.Ascending)
            {
                GridViewSortDirection = SortDirection.Descending;
                DataView dv = new DataView(dt);
                dv.Sort = sortExpression + " " + "desc";
                this.softlistshow.DataSource = dv;
                this.softlistshow.DataBind();
            }
            else
            {
                GridViewSortDirection = SortDirection.Ascending;
                DataView dv = new DataView(dt);
                dv.Sort = sortExpression + " " + "asc";
                this.softlistshow.DataSource = dv;
                this.softlistshow.DataBind();
            }
        }
        catch (Exception ex)
        {
            throw ex;
        }
    }