I have a grid view where i am a template field to delete a row. i want to capture the datakey value for the row.

How do i do this. Following the code:

<asp:GridView ID="gvAllEmployees" runat="server" AllowPaging="True" AllowSorting="True"
            AutoGenerateColumns="False" BackColor="White" BorderColor="#DEDFDE" BorderStyle="None"
            BorderWidth="1px" CellPadding="4" DataKeyNames="UserID" DataSourceID="sdsAllEmployees"
            ForeColor="Black" GridLines="Vertical" HorizontalAlign="Center" Width="100%"
            PageIndex="10" PagerSettings-Mode="Numeric" EmptyDataText="There are no employee records to show."
            EmptyDataRowStyle-CssClass="labeltext" EmptyDataRowStyle-HorizontalAlign="center"
            EmptyDataRowStyle-VerticalAlign="middle" CssClass="gridview">
            <Columns>
                <asp:HyperLinkField DataNavigateUrlFields="UserID" DataNavigateUrlFormatString="~/EmployeeDetails.aspx?UserName={0}"
                    DataTextField="UserID" HeaderText="User ID" SortExpression="UserID" />
                <asp:BoundField DataField="FirstName" HeaderText="First Name" SortExpression="FirstName" />
                <asp:BoundField DataField="MiddleName" HeaderText="Middle Name" SortExpression="MiddleName" />
                <asp:BoundField DataField="LastName" HeaderText="Last Name" SortExpression="LastName" />
                <asp:BoundField DataField="Designation" HeaderText="Designation" SortExpression="Designation" />
                <asp:BoundField DataField="Role" HeaderText="Role" SortExpression="Role" />
                <asp:BoundField DataField="UserName" HeaderText="User Name" SortExpression="UserName" />
                <asp:TemplateField>
                    <ItemTemplate>
                        <asp:ImageButton ID="imgbtDelete" runat="server" ImageUrl="~/Images/Delete.gif" ToolTip="Delete Employee"
                            CausesValidation="false" CommandName="Delete" OnClientClick="return confirm('Pressing OK will delete this employee record. Do you wish to continue?')" />
                    </ItemTemplate>
                </asp:TemplateField>
            </Columns>
            <HeaderStyle BackColor="#6B696B" Font-Bold="True" ForeColor="White" HorizontalAlign="center" />
            <FooterStyle BackColor="#CCCC99" />
            <RowStyle BackColor="#F7F7DE" HorizontalAlign="Center" />
            <AlternatingRowStyle BackColor="White" />
            <SelectedRowStyle BackColor="#CE5D5A" Font-Bold="True" ForeColor="White" />
            <PagerStyle HorizontalAlign="Center" CssClass="pages" />
        </asp:GridView>
    </ContentTemplate>
</asp:UpdatePanel>
<asp:SqlDataSource ID="sdsAllEmployees" runat="server" ConnectionString="<%$ ConnectionStrings:EmployeeTimeTrackerDBConnectionS tring %>"
    SelectCommand="GetAllEmployee" SelectCommandType="StoredProcedure" DeleteCommand="DeleteEmployee"
    DeleteCommandType="storedProcedure" DataSourceMode="DataSet"></asp:SqlDataSource>