//分页
    protected void pageindex()
    {
        try
        {
            SqlConnection mysqlconn = new SqlConnection(publicclass.getconnstr());
            mysqlconn.Open();
            SqlDataAdapter sda = new SqlDataAdapter("select * from UF_POST", mysqlconn);
            DataSet ds = new DataSet();
            sda.Fill(ds, "UF_POST");
            GridView1.DataSource = ds.Tables["UF_POST"];
            GridView1.AllowPaging = true;
            GridView1.PageSize = 10;
            GridView1.DataBind();
            shou.Enabled = true;
            shang.Enabled = true;
            xia.Enabled = true;
            wei.Enabled = true;
            if (GridView1.PageIndex == 0)
            {
                shou.Enabled = false;
                shang.Enabled = false;
            }
            if (GridView1.PageIndex == GridView1.PageCount - 1)
            {
                xia.Enabled = false;
                wei.Enabled = false;
            }
            if (!IsPostBack)
            {
                for (int i = 0; i < GridView1.PageCount; i++)
                {
                    DropDownList1.Items.Add(i.ToString());
                }
            }
            Label1.Text = GridView1.PageCount.ToString();
            Label2.Text = GridView1.PageSize.ToString();
            Label3.Text = GridView1.PageIndex.ToString();
        }
        catch (Exception ex)
        {
            Response.Write(ex.Message);
        }
    }   
    //首页
    protected void shou_Click(object sender, EventArgs e)
    {
        GridView1.PageIndex = 0;
        pageindex();
    }
    //上一页
    protected void shang_Click(object sender, EventArgs e)
    {
        GridView1.PageIndex = GridView1.PageIndex - 1;
        pageindex();
    }
    //下一页
    protected void xia_Click(object sender, EventArgs e)
    {
        GridView1.PageIndex = GridView1.PageIndex + 1;
        pageindex();
    }
    //尾页
    protected void wei_Click(object sender, EventArgs e)
    {
        GridView1.PageIndex = GridView1.PageCount - 1;
        pageindex();
    }
    //跳转
    protected void DropDownList2_SelectedIndexChanged(object sender, EventArgs e)
    {
        GridView1.PageIndex = Convert.ToInt32(DropDownList2.SelectedItem.Text);
        Label3.Text = DropDownList2.Text;
        pageindex();
    }

已经为flase了
代码中还必须把它定为true
GridView1.AllowPaging = true;

在控件属性中没设分页  
但是在代码不加GridView1.AllowPaging = true;
是不能进行代码分页的