datalist 分页显示不用PagedDataSource对象

protected void Page_Load(object sender, EventArgs e)

{              

string series, category;                       

if (!IsPostBack)        { 

string series1 = Series(out series);            

string category1 = Category(out category);            

string cseries = series1 + category1;

 int pageSize = 3;//分页中一页的条数，可以用下拉框选择你喜欢的条数            

string sql="";            

int currentPage = 0;            

if (HttpContext.Current.Request.QueryString["page"] != null)            

{                

currentPage = Convert.ToInt32(HttpContext.Current.Request.QueryString["page"].ToString());//获得当前的页码            

}            

if (currentPage <=1)            

{                

sql = "select top " + pageSize + " * from T_product " + cseries; //第一页的绑定           

}            

else            

{                

sql = "SELECT TOP " + pageSize + " * FROM T_product " + cseries + " and (id NOT IN (SELECT TOP " + (currentPage-1)* pageSize + " id FROM T_product " + cseries + "))";   //后面的页的绑定          

}            

DataTable dt = me.readData(sql);   //  me 是读取数据库的一个类的实例

//我这里想不到好的方法，有没有可以不用读全部的数据，把数据都读出来

  if (ViewState["total"]==null)

            {

                DataTable dt1 = me.readData("select * from T_product " + cseries);

                //int total = dt1.Rows.Count;

                ViewState["total"] = dt1.Rows.Count;

            }

            total = Convert.ToInt32(ViewState["total"].ToString());

           Label1.Text = GetPageNum(dt, DataList1, pageSize, series, category,total );

}

}

/// </summary>

    /// <param name="ds">DataTable实例</param>

    /// <param name="datalistname">DataList名称</param>

    /// <param name="pagesize">分页大小</param>

    public string GetPageNum(DataTable dt, DataList datalistname, int pagesize, string series,string category,total)

    {

        int total = total;

        int page;

        if (HttpContext.Current.Request.QueryString["page"] != null)

            page = Convert.ToInt32(HttpContext.Current.Request.QueryString["page"]);

        else

            page = 1;

        //objPds.CurrentPageIndex = page - 1;

        datalistname.DataSource = dt.DefaultView;

        datalistname.DataBind();

        int allpage = 0;

        int next = 0;

        int pre = 0;

        int startcount = 0;

        int endcount = 0;

        string pagestr = "";

        if (page < 1) { page = 1; }

        //计算总页数

        if (pagesize != 0)

        {

            allpage = (total / pagesize);

            allpage = ((total % pagesize) != 0 ? allpage + 1 : allpage);

            allpage = (allpage == 0 ? 1 : allpage);

        }

        next = page + 1;

        pre = page - 1;

        startcount = (page + 5) > allpage ? allpage - 9 : page - 4;//中间页起始序号

        //中间页终止序号

        endcount = page < 5 ? 10 : page + 5;

        if (startcount < 1) { startcount = 1; } //为了避免输出的时候产生负数，设置如果小于1就从序号1开始

        if (allpage < endcount) { endcount = allpage; } //页码+5的可能性就会产生最终输出序号大于总页码，那么就要将其控制在页码数之内

        pagestr = "共" + allpage + "页" + total + "条&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;";

        pagestr += page > 1 ? "<a href=\"" + HttpContext.Current.Request.CurrentExecutionFilePath + "?page=1&Series=" + series + "&Category=" + category + "\">首页</a>&nbsp;&nbsp;<a href=\"" + HttpContext.Current.Request.CurrentExecutionFilePath + "?page=" + pre + "&Series=" + series + "&Category=" + category+ "\">上一页</a>" : "首页 上一页";        //中间页处理，这个增加时间复杂度，减小空间复杂度        for (int i = startcount; i <= endcount; i++) 

       {

            pagestr += page == i ? "&nbsp;&nbsp;<font color=\"#ff0000\">" + i + "</font>" : "&nbsp;&nbsp;<a href=\"" + HttpContext.Current.Request.CurrentExecutionFilePath + "?page=" + i + "&Series=" + series + "&Category=" + category + "\">" + i + "</a>";         }

        pagestr += page != allpage ? "&nbsp;&nbsp;<a href=\"" + HttpContext.Current.Request.CurrentExecutionFilePath + "?page=" + next + "&Series=" + series + "&Category=" + category + "\">下一页</a>&nbsp;&nbsp;<a href=\"" + HttpContext.Current.Request.CurrentExecutionFilePath + "?page=" + allpage + "&Series=" + series + "&Category=" + category + "\">末页</a>" : " 下一页 末页";

        return pagestr;    

}