Gridview Timer定时刷新无效，为什么？要求代码最好

asp.net:
我把一个gridview，timer放进updatepanel里，希望能自动刷新gridview里的内容，但gridview没反应，
我将gridview数据绑定代码放进一个button点击事件里，将button放进同一个updatepanel里，点击按钮，gridview可以刷新一次显示最新数据，可在timer的tick事件里就没任何反应，更可怕的是我在timer_tick中强行触发button_click事件：button_click(null,null),居然也没反应！！反正就是触发不了timer，能用快速度解决下吗？下面是我的代码：后台代码：Default2.aspx.cspublic partial class Default2 : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        this.divGridView.Attributes["style"] = "width:570px;overflow:auto;"
                + (GridView1.Rows.Count >= 25 ? "height:480px" : string.Empty);
        ShowAuthors();
    }
    protected void Timer1_Tick(object sender, EventArgs e)
    {
        GridView1.DataBind();
    }
    public void ShowAuthors()
    {
        OracleDataAdapter sda = new OracleDataAdapter("select rownum as id,topictrim,topicname from t_topic", "Data Source=NAVECODB_120;user=System;password=1");
        DataTable dt = new DataTable();
        sda.Fill(dt);
        GridView1.DataSource = dt;
        GridView1.DataBind();
    }    protected void Button1_Click(object sender, EventArgs e)
    {
        ShowAuthors();
    }
}前台代码：Default2.aspx
<body>
    <form id="form1" runat="server">
    <div>
    <div id="divGridView" runat="server" >
            <asp:UpdatePanel ID="UpdatePanel2" runat="server">
                <ContentTemplate>
            <asp:ScriptManager ID="ScriptManager1" runat="server">
            </asp:ScriptManager>
                    <asp:Timer id="Timer1" runat="server" Interval="100" OnTick="Timer1_Tick">
                    </asp:Timer>
                    <asp:GridView ID="GridView1" runat="server" CellPadding="4" ForeColor="#333333" GridLines="None">
                        <RowStyle BackColor="#F7F6F3" ForeColor="#333333" />
                        <FooterStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
                        <PagerStyle BackColor="#284775" ForeColor="White" HorizontalAlign="Center" />
                        <SelectedRowStyle BackColor="#E2DED6" Font-Bold="True" ForeColor="#333333" />
                        <HeaderStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
                        <EditRowStyle BackColor="#999999" />
                        <AlternatingRowStyle BackColor="White" ForeColor="#284775" />
                    </asp:GridView>
                    
                </ContentTemplate>
                
            </asp:UpdatePanel>
        <asp:Button ID="Button2" runat="server" Text="刷新" OnClick="Button1_Click" />
    </div>
    
    </div>
    </form>
</body>