手写分页个人感觉还能优化，甚至抽象出来，需要高手讲解

本来就是想来学习下手写分页或者自己写下分页逻辑，就当是一次练习，数据用的是sql2005，数据量是432W。

首先先感谢国家。然后在感谢csdn和群里的朋友跟我一起讨论。当然拉我知道我的做法不是最好的，但是手写一个是挺费劲的。

下面贴代码

private SqlConnection con = new SqlConnection("Data Source=.;Initial Catalog=test;Persist Security Info=True;User ID=sa;Password=123456");
protected void Page_Load(object sender, EventArgs e)
{
    //数据显示，跟分页分开操作
        con.Open();
        DataSet ds = new DataSet();
        int num =0;
        if (string.IsNullOrWhiteSpace(Request["page"]) ||Convert.ToInt32(Request["page"])<=1)
        {
            num = 0;
        }
        else
        {
            num =Convert.ToInt32(Request["page"])-1;
        }
        string sql = "select top 20 id,name,sex,age from aa where id not in (select top (20*" + num + ") id from aa order by id desc) order by id desc";
        SqlDataAdapter da = new SqlDataAdapter(sql, con);
        da.Fill(ds, "0");
        con.Close();
        GridView1.DataSource = ds.Tables[0];
        GridView1.DataBind();
}
//分页处理
public string pageIndex()
{
    int num = 0;//当前页码
    if (string.IsNullOrWhiteSpace(Request["page"]) || Convert.ToInt32(Request["page"]) <= 1)
    {
        num = 1;
    }
    else
    {
        num = Convert.ToInt32(Request["page"]) ;
    }
    //获取到数据库里面的全部数据条数，我没用存储过程用的是sql语句，有的回说存储过程效率高。
    //亲 我测试数据库是432W数据
    //亲 我查询的是一列，
    //亲 最重要的一点是我不会存储过程
    //亲 我知道这么查效率低哦！~但是我只查一次！~
    StringBuilder sb = new StringBuilder();
    con.Open();
    string sql = "select count(id) from aa";
    SqlCommand com = new SqlCommand(sql, con);
    int count = Convert.ToInt32(com.ExecuteScalar());
    con.Close();
    int page = 0;//页总数
    page = (int)Math.Ceiling((decimal) count / 20);
    //int from = num / 10 * 10 + 1;//起始页
    int from = 0;
    int to = 0;　　 　　//计算极值
    if (from % 10 == 0)
    {
        int tmp = num - 1;
        from = (tmp / 10) * 10 + 1;
        to = tmp / 10 * 10 + 11;
    }
    else
    {
        to = num / 10 * 10 + 11;//终止页
       from = num / 10 * 10 + 1;
    }
 
    if (num != 1)
    {
        sb.AppendLine("<a href='?page=" + (num - 1) + "'>上一页</a>");
    }
    else
    {
        sb.AppendLine("<strong>上一页</strong>");
    }
    for (int i = from; i < to && i < page; i++)
    {
        if (i == num)
            sb.AppendLine("<strong>"+i+"</strong>");
        else
            sb.AppendLine("<a href='?page=" + i  + "'>" + i + "</a>");
    }
    if (to - from >= 10)
    {
        sb.AppendLine("<a href='?page=" + (from + 10) + "'>...</a>");
    }
    if (num <= page)
    {
        sb.AppendLine("<a href='?page=" + (num +1) + "'>下一页</a>");
    }
        return sb.ToString();