Stop postback on user click on grid

Question

I'm trying lot of code on this but still not get any corect answer, My problem is i have a spread .net grid when i click on grid, postback occur i dont need this postback in any case, I also applied ajax control toolkit still my problem not resolved can any one help me.

ASPX

<asp:ScriptManager ID="ScriptManager1" runat="server" />
<asp:UpdatePanel ID="UpdatePanel1" runat="server" UpdateMode="Conditional">
    <ContentTemplate>
        <farpoint:FpSpread ID="FpSpread2" Visible="False" Style="z-index: 100" runat="server" BorderWidth="1px" Width="90%" BorderStyle="Solid" BorderColor="Black" CommandBar-ButtonType="PushButton" EnableClientScript="False">
            <Sheets>
                <farpoint:SheetView  SheetName="Sheet1">
                </farpoint:SheetView>
            </Sheets>
        </farpoint:FpSpread>
     </ContentTemplate>
</asp:UpdatePanel>