ajax局部刷新世界

为什么我点了前进、后退等按钮还是整个页面都刷新呢？请各位帮帮忙解决，我的要求是局部刷新aspx页贴出一部分
<asp:ScriptManager ID="ScriptManager1" runat="server">
                                    </asp:ScriptManager>
                                    <asp:UpdatePanel ID="up" runat="server" ChildrenAsTriggers="False" RenderMode="Inline"
                                        UpdateMode="Conditional">
                                        <ContentTemplate>
                                            <asp:DataList ID="dlrelated" runat="server" RepeatDirection="Horizontal" ShowFooter="False"
                                                ShowHeader="False" Width="100%" RepeatColumns="1" CellSpacing="15">
                                                <ItemTemplate>
                                                    Item:<%# DataBinder.Eval(Container,"DataItem.p_xh") %>
                                                </ItemTemplate>
                                            </asp:DataList>
                                            <div style="width: 100%; background-color: #ffaf00; text-align: right; color: black;">
                                                <asp:LinkButton ID="FirstLB" runat="server" OnCommand="LinkButton_Click" CommandName="first"><img src="../images/product/ico_first.gif" alt="" style="border:0px;" /></asp:LinkButton>&nbsp;&nbsp;&nbsp;
                                                <asp:LinkButton ID="PreviousLB" runat="server" OnCommand="LinkButton_Click" CommandName="prev"><img src="../images/product/ico_prev.gif" alt="" style="border:0px;" /></asp:LinkButton>&nbsp;&nbsp;&nbsp;
                                                <asp:LinkButton ID="NextLB" runat="server" OnCommand="LinkButton_Click" CommandName="next"><img src="../images/product/ico_next.gif" alt="" style="border:0px;" /></asp:LinkButton>&nbsp;&nbsp;&nbsp;
                                                <asp:LinkButton ID="EndLB" runat="server" OnCommand="LinkButton_Click" CommandName="end"><img src="../images/product/ico_last.gif" alt="" style="border:0px;" /></asp:LinkButton>
                                                &nbsp;&nbsp; Current<asp:Label ID="CurrentLbl" runat="server" ForeColor="white"></asp:Label>/<asp:Label
                                                    ID="TotalLbl" runat="server" ForeColor="white"></asp:Label>page
                                                <asp:LinkButton ID="JumpLB" runat="server" OnCommand="LinkButton_Click" CommandName="jump"
                                                    ForeColor="white">Jump to</asp:LinkButton>&nbsp;NO.
                                                <asp:TextBox ID="TextBox1" runat="server" Width="53px" Height="13px"></asp:TextBox>page
                                            </div>
                                        </ContentTemplate>
                                    </asp:UpdatePanel>代码页贴出一部分
public void LinkButton_Click(Object sender, CommandEventArgs e)//自己编写的按钮点击事件
    {
        CurrentPage = (int)ViewState["PageIndex"];//获得当前页索引
        PageCount = (int)ViewState["PageCount"];//获得总页数
        string cmd = e.CommandName;
        //判断cmd，以判定翻页方向
        switch (cmd)
        {
            case "prev"://上一页
                if (CurrentPage > 0)
                {
                    CurrentPage--;
                }
                break;
            case "next":
                if (CurrentPage < (PageCount - 1))
                {
                    CurrentPage++;//下一页
                }
                break;
            case "first"://第一页
                CurrentPage = 0;
                break;
            case "end"://最后一页
                CurrentPage = PageCount - 1;
                break;            case "jump"://跳转到第几页
                if (TextBox1.Text.Trim() == "" || Int32.Parse(TextBox1.Text.Trim()) > PageCount || Int32.Parse(TextBox1.Text.Trim()) <= 0)//如果输入数字为空或超出范围则返回
                {
                    return;
                }
                else
                {
                    CurrentPage = Int32.Parse(TextBox1.Text.ToString()) - 1;
                    break;
                }
        }
        ViewState["PageIndex"] = CurrentPage;//获得当前页
        DataListBind();//重新将DataList绑定到数据库
        up.Update();
    }