button not firing when put inside gridview

Hi, My gridview is placed inside UpdatePanel. This I ave used to prevent page refresh in paging. I have also a button inside the gridview. After I put the UpdatePanel, it stops pagerefresh on paging click but it has also stopped click event of button.

<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
<asp:GridView ID="GridView1" AllowPaging="true" PagerStyle-CssClass="pgr" OnRowDataBound="GridView1_RowDataBound"
AlternatingRowStyle-CssClass="alt" AutoGenerateColumns="false" runat="server"
PageSize="8" OnPageIndexChanging="GridView1OnPageIndexChanging" DataKeyNames="MainBreakDownReasonID">

<HeaderStyle BackColor="#465c71" ForeColor="White" />
<Columns>
<asp:BoundField DataField="MainBreakDownReason" ItemStyle-Width="330" HeaderText="Process" />
<asp:BoundField DataField="MainBreakDownReasonCount" ItemStyle-Width="130" HeaderText="Count" />
<asp:BoundField DataField="BreakDownTime" HeaderText="Time(mins)" ItemStyle-Width="130"/>

<asp:TemplateField ItemStyle-Width="30" >
<ItemTemplate>
<asp:Button ID="Button1"  Text="Get Trend" runat="server" OnClick="GridView1Button1_Click1"/>
</ItemTemplate>
</asp:TemplateField>

</Columns>

</asp:GridView>
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="GridView1" EventName="PageIndexChanging" />
<%--<asp:AsyncPostBackTrigger ControlID="Button1" EventName="Click" />--%>
</Triggers>
</asp:UpdatePanel>

Please suggest me what wrong I am doing.

I have also tried doing this:

protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.DataRow)
{
Button button = (Button)e.Row.FindControl("Button1");
AsyncPostBackTrigger trigger = new AsyncPostBackTrigger();

trigger.ControlID = button.UniqueID;
trigger.EventName = "Click";
UpdatePanel1.Triggers.Add(trigger);

ScriptManager1.RegisterAsyncPostBackControl(button);
}
}

but nothing works..

pls help ..