I Want to Avoid Gridview SelectindexChange Method on a Perticular Column Select.

Sir, i have a Gridview in which i am using Gridview_SelectIndexChanged Method.In my gridview i have take in first COlumn an Imagebutton. i Need that when i click on Image button then SelectindexChanged not do there Work. and if i click on other Columns then its works fine.. My code is:-

<asp:GridView ID="GridView3" runat="server" DataKeyNames="ClassesID" CssClass="mGrid"
    PagerStyle-CssClass="pgr" AlternatingRowStyle-CssClass="alt" AutoGenerateColumns="false"
    GridLines="Horizontal" OnRowDataBound="GridView3Bound" Width="100%">
    <Columns>

        <asp:TemplateField>
            <ItemTemplate>
                <asp:ImageButton ID="ImageButton2" runat="server" Style="cursor: pointer"  ImageUrl="~/images/plus.png" CommandName="Select" OnClick="Plus"/>
        </ItemTemplate>
        </asp:TemplateField>
        <asp:TemplateField HeaderText="Hostel" HeaderStyle-Width="350px">
            <HeaderTemplate>
                <span style="vertical-align: top">Class </span>
            </HeaderTemplate>
            <ItemTemplate>
                <asp:Label ID="lblhos" runat="server" Text='<%# Bind("Code") %>'></asp:Label>
            </ItemTemplate>
        </asp:TemplateField>
        <asp:BoundField DataField="P" HeaderText="Present" SortExpression="noofroom"
            HeaderStyle-Width="350px" HeaderStyle-HorizontalAlign="Right" ItemStyle-HorizontalAlign="Right" />
        <asp:BoundField DataField="a" HeaderText="Absent" SortExpression="full"
            HeaderStyle-Width="350px" HeaderStyle-HorizontalAlign="Right" ItemStyle-HorizontalAlign="Right" />
        <asp:BoundField DataField="per" HeaderText="%" SortExpression="Vacant"
            HeaderStyle-Width="350px" HeaderStyle-HorizontalAlign="Right" ItemStyle-HorizontalAlign="Right" />

        <asp:TemplateField ItemStyle-HorizontalAlign="Right" HeaderStyle-Width="50px" ItemStyle-Width="30px">
            <ItemTemplate>
                <asp:ImageButton ID="pri2" Width="30px" Height="30px" CommandName="Select"
                    CommandArgument='<%# Eval("ClassesID") %>' CausesValidation="False" ImageUrl="~/Images/printer.png"
                    runat="server" />
            </ItemTemplate>
        </asp:TemplateField>

        <asp:TemplateField Visible="false">
            <ItemTemplate>
                <asp:Label ID="ClassesID" runat="server" Visible="false" Text='<%# Bind("ClassesID") %>'></asp:Label>
            </ItemTemplate>
        </asp:TemplateField>

    </Columns>

</asp:GridView>

Protected Sub GridView3_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles GridView3.SelectedIndexChanged
      

      
        Dim i As Integer = GridView3.SelectedIndex

        Dim DataKey As String = GridView3.DataKeys(GridView3.SelectedIndex).Value
        Session("ClassesID") = DataKey
    End Sub