ASP.NET中按名称排序Asc和GridView中的LastName描述

Question

我有这个Gridview，我有三列：ID，Name和LastName我希望按名称Descending和LastName Ascending排序，但我不能正确地做到这一点。另外，忽略ListBox lstPeople，我只需要将它应用到Gridview grvPeople。谢谢！

aspx.cs：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using Domain;

namespace WebInterface
{
public partial class myClass: System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        lstPeople.DataSource = controllerclass.Instance().getPeople();
        lstPeople.DataTextField = "Data";
        lstPeople.DataValueField = "ID";
        lstPeople.DataBind();

        grvPeople.DataSource =controllerclass.Instance().getPeople();
        grvPeople.DataBind();

        if (!IsPostBack)
        {
            List<People> myList = controllerclass.Instance().getPeople();
            myList .Sort(new People.OrderbyName());
            myList .Sort(new People.OrderbyLastName());
            Session["sortedView"] = myList;
            BindData(myList);
            Session["filter"] = "Name";
            Session["direction"] = SortDirection.Ascending;
        }
    }

    protected void BindData(List<People> p)
    {
        lstPeople.DataSource = p;
        lstPeople.DataBind();
    }

    protected void grvPeople_Sorting(object sender, GridViewSortEventArgs e)
    {
        List<People> myList = (List<People>)Session["sortedView"];
        if (e.SortExpression == "ID") myList.Sort(new People.OrderbyID());
        if (e.SortExpression == "Name") myList.Sort(new People.OrderbyName());
        if (e.SortExpression == "LastName") myList.Sort(new People.OrderbyLastName());

        if (e.SortExpression == Session["filter"].ToString().Trim())
        {
            SortDirection aux = (SortDirection)Session["direction"];
            if (SortDirection.Ascending == aux)
            {
                Session["direction"] = SortDirection.Descending;
                myList.Reverse();
            }
            else
            {
                Session["direction"] = SortDirection.Ascending;
            }
        }
        Session["filter"] = e.SortExpression;
        Session["sortedView"] = myList;
        BindData(myList);
    }

    protected void grvPeople_PageIndexChanging(object sender, GridViewPageEventArgs e)
    {
        grvPeople.PageIndex = e.NewPageIndex;
        BindData((List<People>)Session["sortedView"]);
    }
  }
}